The Marvelous Misadventures of Flapjack/WMG

The little old lady is related to Flapjack
Most likely his grandmother. Obviously, this implies that Flapjack's parents either abandoned the pair of them or are dead.

Stormalong rests directly atop the ruins of Candied Island.
Which is why nobody ever finds it!

Bubbie murdered Flapjack's real parents.
Think about it. Bubbie was hesitant to answer Flapjack's question (if Bubbie remembered where he came from) in the episode "Oh Brother!" She told Flapjack a story about finding baby Flapjack in a bed of seaweed which, given the crappy world the characters inhabit, seems improbably idealistic. More likely, Bubbie was covering up the truth that she very badly wanted a child but for some reason couldn't have one, and she somehow killed Flapjack's parents (likely by smashing their boat) and taking baby Flapjack to raise as her own.
 * Additionally, in another episode, Bubby mentions her "babies", as in plural. One can infer that Bubby has "adopted" other children in the past, who have grown up and moved out. K'Nuckles may be one of these, and is possibly the Stormalong equivalent of a grown man living in his mother's basement. Additionally, we never see any other whales on the show; due to extensive whaling, Bubby may be the last of her kind and in a state of denial, adopting and raising human children in a futile attempt to "save her species".
 * We do see another whale, one who kidnaps kids from their guardian animals and makes them work on his laundry island. She may be the last female whale though.
 * Possible reasons that Bubbie would be childless: She's barren, she's considered unattractive by whale standards, she's a Christmas Cake, or she has some position in whale society that prevents such things. None of these things are contradictory. Therefore, all of them are the case.
 * And considering how uncomfortable she got when Flapjack talked about squishing people because she's so big...
 * Alternately, Bubbie was telling the truth and the reason Flapjack was found in a pile of seaweed is because he's one among many children of Poseidon himself. He was presumably dumped there by Poseidon who wanted nothing to do with him or maybe his mother died in sea trying to protect her child from him. The reason Flapjack is mortal is simply the results of Gods screwing around with mortal women (granted, that would make Flapjack half God, but that's another theory altogether). Perhaps Bubbie's hesitation to tell Flapjack the "truth of his birth" is fear he'd one day get the wise idea to leave her and seek his true parents.

The Marvelous Misadventures take place in the same extended universe as The Decemberists' more nautical themed songs.
Particularly The Mariner's Revenge Song. This will end badly for both. Flapjack may even be the protaganist of The Mariner's Revenge Song, and is destined to kill the man who gave his mother the consumption that drove her mad and killed her. His Keet-like enthusiasm is only the buildup to the biggest cutie-breaking childrens' animation has seen. Just watch out once he gets a job at a priory. (Or, alternately, his mother was the mother in A Cautionary Tale. And this is how you're fed...)
 * Is it strange that I thought the exact same thing the first time I heard "The Mariner's Revenge Song"? I was actually coming here to write this exact same prospect.

Candied Island is in fact Marzipan City
I SMELL CROSSOVER!
 * So what you're basically saying is...Candied Island is in space. And it's carried around by a giant who is reminiscent of Atlas. And it's ruled over by the King of All Cosmos. THIS SOUNDS AWESOME.
 * I second the previous poster's ":D".
 * The King of All Cosmos!? Candy katamari crossover ensues! :D

Marzipan City is the place where Flapjack was born
He follows the Marzipan City Theme Naming of being named after food. The crossover from above will happen when he searches for his real parents.

Candied Island is really Candy Die Land, where old candy goes to die.

 * Making their discovery of it that much more of a Crapsack World.
 * Wow. That's actually fantastically depressing. I like the Marzipan City WMGs more :p
 * Shhh Van Orman might hear you
 * Nah, even if he reads this, he might probably put Candied Island as somewhere else, which makes...

Candied Island is the Afterlife
K'nucles probably was there for just a while because he passed a near-death experience, and is delusional on how he got there. After all, it would be a paradise for such Crapsack World that Stormalong is. Someday, they'll find the Candied Island, but if they don't return quickly enough... Poor Bubbie, she'll cry so much...
 * Alternatively, Stormalong is the Afterlife; more specifically, Kusajishi, even if it's some sort of an Alternate Universe. Allusions to K'nuckles being Kenpachi Zaraki and Flapjack being Yachiru are welcome, too.
 * Oh my God, that's weird. I was going to plant an Epileptic Tree just like this. Granted, it's not such a big leap from the above, but it would explain how they reached Candied Island after falling from the moon. They weren't really reeled back in; it was a near death experience, albeit a tasty one.

Candy Wife is a resident of Candied Island, where her husband gets his goods and/or Candy Prostitutes.

 * Self-explanatory.
 * Of course! I can't believe I didn't thought of it myself! But wait... Why didn't K'nuckles and Flapjack?
 * Because they're idiots

In the future, Candied Island will become the future site of Superjail.
Just look at this image and tell me I'm wrong.
 * Not an argument against it (it is part of my personal cannon now) but just one little observation. The Warden has an irrational hatred of children; ordering the Littlest Cancer Patient to be burned on sight is the most memorable manifestation of that hatred. So he probably wouldn't keep a picture of a child around. Still brilliant, though.
 * Well, consider that the child in question IS his great-grandfather, and the Warden does possess a large portrait of his father.
 * Not as a child, though.
 * I thought Flapjack looked more teenage in that picture.
 * Alternativly Candied Island is Super Jail, the Warden made the candy wrapper maps and spread the rumor that it was made of candy, just so he could catch some pirates.
 * Hmm this would explain why Grinderbread men were seen whipping prisoners working in a candy feild that one this

Flapjack grows up to be Aquaman. As an old man, he becomes Popeye.
It had to happen, and you know it.
 * Not so old, but at his late thirties; that's Popeye's canon age, after all. At one point, he becomes Anthony Hope. Victorian London must look pretty good when you've grown up in Stormalong Harbor. At least nobody has barnacles on their faces.

Harvey actually cares about the whales/squids/whatever he kisses.
Harvey runs Laundry Island and feels bad for Bubbie and the others for always having to do others' laundry. So he kisses them and takes those that are forcing them to do the laundry of their hands and make them do others' laundry so they know what it feels like.

Candied Island is, in reality, Raftel Island
And a huge candy-filled treasure chest is Gold Roger's One Piece. Crossover ensues.

K'nuckles is Flapjack's father
Let's just say that Flapjack takes a lot of the pyhsical appearance of whatever woman K'nuckles got intimate with.

The reason Flapjack was even greenlit was to make the other cartoons network shows seem better by comparison.
I really don't have to explain this one, do I?
 * This troper disagrees with this statement, it's surreality makes it unique and genuinely funny.
 * Considering that this show is basically the best cartoon on TV right now, I'm pretty sure that's false.
 * Could still be true, it just turned out much better than Cartoon Network ever expected it would.
 * So then it would be a Springtime for Hitler, except everyone won out?

Candied Island is where a local apocalypse happened.
Everyone was coated in a thin layer of instantly-hardening candy coating and suffocated. Thus, Candied Island, and not Candy Island.

Thurop is channeling Alan Moore via his beard
Where else do you think he gets "Inspiration"?

It's all in Flapjack's head and he's actually a modern drug addict teenage boy
Flapjack is actually a modern child from the slums whose parents (K'nuckles and Bubby) always promised take him to the sea, but they never did. He's unaware of his father's obvious alcoholism/drug addiction (thinking it's just candy), the borderline protectionism of his mother and could be possibly molested by Dr. Barbar (that's why he's so creepy). So, since he can't handle the real life and feels his father so far he got into his father's addiction, the candies, candy island is then nirvana/afterlife whereas there's no pain.

Captain K'nuckles is a Diglett
Much as it pains me to use that name, I think more people recognize it than 'Digda'. .. Um, well, see, if all his parts are removed he's just a round-topped cylindrical lump with eyes and a nose.
 * I thought the "nose" of a Diglett was actually a mouth and a single tooth. Oh dear, I hope I didn't just blow everyone's minds...

Captain K'nuckles is swiftly heading toward the Moral Event Horizon
Sometimes, this troper just does not get the relationship between Flapjack and K'nuckles. Is he supposed to be his deadbeat uncle? Abusive father? He really does act like an abusive father. K'nuckles is toeing the line between hilarious misanthrope and actual villain.

Captain K'nuckles is actually an older Bloo.
Just think, He's blue, he has stumps for hands and no real feet, his nose mismatches the rest of his body, he's grown a grand total of ONE hair, has delusions of grandeur over his "adventures", hangs around a kid who idolizes him, lives in a candy-obsessed world (a nod to Mac's Berserk Button), can get more childish than the kid he hangs around with, he forms harebrained schemes, and... you know what, let me stop here. It's making way too much sense.

Tee Hee Tummy Tums is Johnny Depp.
He's the most beautiful man in the world, correct?

This is Candle Cove.
There is a talking whale, who acts as a ship and is referred as one. Laughingstock. There is a cowardly pirate. Pirate Percy. There is a boy who is constantly referred to as a girl and is friends with the cowardly pirate. Janice. Candle. Candy. And it's all extremely Nightmare Fuel.
 * Alternatively, the setting takes place in the universe formerly occupied by Janice's imagination(Candle Cove). Janice died, thus causing Candle Cove to be destroyed(hence the final episode with everyone screaming), but it wasn't gone for long. When a new world was created in that space, the characters were reincarnated with somewhat different personalities. The Skin-Taker became Dr. Barber(losing most of his wit but gaining a creepy monotone and retaining his love for vivisection), the Laughingstock became Bubby, Pirate Percy became K'nuckles(changing from a lovable coward to a jerkass), and Janice herself was reincarnated as Flapjack. God knows who Horace became. Could be Eight-Armed-Willy.

The Show is so Nightmare Fuel-rifffic Because...
It's sole purpose is to provide images for screamers. Just look at some of the examples provided here. If iCarly is for youtube poop, then Flapjack is for screamers.

The Real Adventurer is Flapjack's real father.
They both have blonde hair, blue eyes and of course love adventuring. Also, in "Oh You Animal", The Real Adventurer is upset when

Capt'n K'nuckles actually was a captain prior to meeting Flapjack and Bubbie
Not only was he a captain with his own ship, Lolly Poop Deck, Peppermint Larry, and Dr. Barber were his crew. They used to be competent explorers until they found Candied Island. K'nuckles and Peppermint Larry both fell in love with Candy Wife, brought much strife to the paradise of Candied Island, so she cursed them with incompetency in their field.

Candied Island is cursed (Or possibly haunted) in such a way that the only way on and off the island is by accident.
Whenever anyone tries to find it, they fail, and all anyone knows about the island is that it's covered in candy. Is there any kind of settlement there? Nobody knows. Are there any dangerous monsters there? Nobody knows. Can you ever leave it if you choose? Nobody knows. No map exists to it's location, no one's ever returned with coordinates to it's location, even sea creatures can't find it easily. It must be cursed, or at least haunted.
 * Well, there was a map, but it didn't work because it didn't have the right X to mark the spot.

Capt'n K'nuckles is The Flying Dutchman.
Capt'n K'nuckles, tired of getting absolutely no respect in life, chooses to haunt the seven seas, impersonating the ghostly captain of Flying Dutchman. Being noncorporeal, he's able to fudge the appearance, but the voice remains the same.

Flapjack grows up to be Anthony Hope
Remember how in the finale,  Well, , the trio ends up in London and decide to make the city their new home. Anthony Hope may have actually have been Flapjack's legal name, or Flapjack had to recieve a legal name when the trio first arrived in London.

The reason why Anthony/Flapjack may have been so pleasant to Todd is because Todd reminds him of K'nuckles. They certainly have similar voices, for one.

Flapjack takes place in the same Universe as Fist of the North Star
In some far-off pocket of the world, the oceans are returning. Besides, I dare you to explain this.

Finn and Flapjack are long lost brothers or cousins.
Word of God created both of them. Both characters like adventure. They have a sidekick that normally gets them in or out of trouble. There's a female heroine that makes random cameos...
 * Alternatively, Finn could be a descendant of Flapjack.

Van Ormann was inspired by the works of Al Duvall.
Duvall is an American musician who sings modern-day songs In the Style Of long-since-dead blues musicians. Crapsack Worlds are his favorite theme. The link is most prominent on the works in which Duvall addresses the rather dystopian setting with a light-hearted mood, such as the album "The Timid Mischief" (especially "The Day Bartender" and "Mary Mack") as well as bits and pieces from "Recluses Unite" ("Dark Inside" for example) and on the instrumentation in the cartoon(especially the end credits).

In regards to another WMG encountered on WMG: Adventure Time, Candied Island is actual the Candy Kingdom
If a sailor had been traversing the dangerous seas and caught a glimpse of a shore made entirely of candy, he'd assume it was an island, a Candied Island. Not to mention the animation style is pretty similar.

Flapjack is a Spiritual Successor to Candle Cove.
Well, Candle Cove does apparently feature a kid and an imcompetent pirate going on adventures in a living ship...