Frasier/WMG

Daphne is a member of MI 5, the British Intelligence.
She's after information about one or more perhaps-unresolved cases ex-cop Martin Crane (the father) had worked on. Her accent keeps changing, as if she wasn't really from Manchester and her folksy manner is a facade, and her attitude towards Martin keeps changing. She was hired in as a physical therapist, and very quickly became the family's maid so she could have an excuse to shuffle through his belongings and get their mail. She marries Niles so she can stay close to Martin and keep at it...falling for him later by coincidental luck.
 * Must be a really important case for Daphne to keep up the façade for 10 years or so.

Maris is an alien.
This only makes sense, given all the descriptions of her.
 * Her fencing instructor did describe as a "not quite human woman".

Frasier has been in an asylum since his suicide attempt on Cheers
This is why his Cheers friends rarely show up -- they aren't allowed to. Lilith shows up every once in a while for pity sex. His dad, like he said on Cheers, is dead; the one we see is just an invention to help make his life bearable. His radio show is really his giving advice to other inmates. His brother is, maybe, a manifestation of who he wishes to be -- younger, slimmer, smarter, lucky ...but Maris is an indication of 'reality'. We never see her because she doesn't exist. She's a crack in the system.
 * But Frasier does see Maris several times, for example in the 5th season episode "Voyage of the Damned". It's only the viewers who don't see her. So, if Maris being The Ghost is supposed to indicate mental illness, it's the viewers who are crazy.
 * She's just visiting him and keeping up the illusion. People do visit people in asylums, you know.

Daphne forced Niles to marry her
The only reason Niles "didn't notice" her attraction to him is because he didn't love her. Niles isn't stupid! But Daphne did something off-camera and now he is forced to love her.
 * Er, shouldn't the names be the other way round?

It's all a fake
Frasier did move to Seattle from Boston, but he lucked out onto the first bit of Internet and has been emailing his old friends long stories about his awesome new life and friends and family. Only his long-established self-loathing screws up his Fanfic, and then the comedy appears.
 * But he's clearly on the radio, and Sam heard his radio show when he was in Seattle. Explain that, sir!
 * The events Frasier described are different from the ones Sam actually experienced. Feeling sorry for the guy, Sam decides to keep quiet and goes along with it.
 * Same thing for Woody.

Frasier gets back together with Lilith after the events of the show
In one of the episodes of Cheers, there is a distant flash forward to when Frasier dies, and Lilith is mentioned as his wife. That's it, but that's sufficient. Here's the clip.
 * In Lilith's final appearance in the show, in the season 11 episode "Guns 'n Neuroses", it certainly seems like she and Frasier have reconciled the differences they used to have in the past. And due to the show's open ending, we never know if Frasier ends up in a lasting relationship with Charlotte. So Frasier getting back together with Lilith would actually be kinda fitting: during the course of the show he has many relationships, some of them longer (Lana, Fay, Charlotte), some of them shorter (most others), but it's Lilith he always keeps returning to.

Leland, in the episode "Fathers And Sons," was lying about being gay and is their biological father
Sure, things like hobbies in common could easily be a coincidence. After all, these hobbies are one of the reasons why Leland and Hester got along so well; and Hester went on to instill the love for these things into a young Frasier and Niles. But Leland also looks rather like Frasier and Niles, and has a similar hair colour to the two boys (a hair colour neither Hester nor Martin share). And he has a number of allergies in common with Niles.

Of course, when Martin asks him what's up, he clearly understands what he's getting at quickly and tells Martin that he is gay. But, as earlier episodes went to great lengths to tell us, a cultured way of speaking and a passion for the finer things don't indicate that someone is gay.

Why did he lie to Martin? If your secret lover's husband asked you if you were the father of his children, then you might lie, too.


 * Leland, knowing he would probably never see Martin again, only told him he was gay to give Martin some peace of mind. (Note: I consider this Poison Oak Epileptic Trees.]]
 * After I watched that episode a time or two the same idea occurred to me. I thought I may have stumbled into a bit of Fridge Brilliance there (Fridge Horror??) and scrutinized his performance during his last scene much more carefully the next time I saw it. I did not note any sign that he was just playing dumb. Of course that could just mean the character is good at playing dumb....
 * Culture and "a passion for the finer things" don't automatically make you gay, but they don't automatically rule out of the possibility, either.
 * I'd just like to add, I always found that the way Leland said "I'm gay" sounded sort of out of the blue, like he came up with it on the spot.
 * Watch it again. He does not just suddenly say, "I'm gay." What he says is, "Enough to reveal to her the fact that I was gay," and in response to Marty asking him how much he loved Hester. It's anything but out of the blue: he's answering a question, and both his performance and the wording of his line ("You know, forty years ago people weren't as understanding about those things as they are now...") suggests not that he's desperately improvising a lie but that he is matter-of-factly discussing something that he believes Marty already knew in the first place. Roz has many good points about how Frasier and Niles, despite being the opposite of Marty in their lifestyle choices, still seem to have inherited quite a lot from him.
 * When Leland says that line, there's a notable pause between the "enough to" and "reveal to her I was gay" bits. This pause is what makes it seem like he's coming up with an explanation that would satisfy Marty on the spot. On the other hand, you could also interpret the pause as Leland having difficulties admitting such a sensitive thing about himself. It's perfectly possible that the writer, or the actor, wanted that scene to be a bit ambiguous. And like Roz says in the episode, it doesn't matter if Leland really is the biological father of Frasier and Niles: Marty is the one who raised them, he is their real father.
 * A good point: Who cares if they're biologically related? If you love someone, it doesn't matter. Love is way stronger than genes.

Niles and Roz slept together after the episode Decoys.
Their attempts to break up Donny and Daphne so they could have them for themselves backfired horribly, resulting in the two of them becoming closer. They both needed comfort and, well, we know how Roz likes to be comforted, and they were in that rustic cabin...

Frasier along with cheers takes place in the DCU and Frasier and Niles Crane are both related to Jonathan Crane(Aka Scarecrow
Both Niles and Frasier are pychiatrists, however there is a dark secret they keep hidden from the cast of cheers. Jonathan Crane is in fact their Granduncle. Their Father's Uncle. Frasier's Father knows full well about Jonathan, and this is why he tried to keep himself and his sons distant from intellectualism, for fear of them ending up like their infamous Relative, Scarecrow. This is why Frasier moves to seattle in reality. to get as far away from Gotham (which is on the east coast) as possible.
 * Perhaps he was their goduncle who died. ("Dad, there's no such thing as a goduncle!") He seemed, from what we've heard, to have taken a great pleasure from scaring people--doing things such as dropping his glass eye into his mashed potatoes and declaring, "I'm watching what I eat!" Puns and sadistic fearmongering? You may have a point. Which brings up the question of how Scarecrow died in this universe and whether Frasier knew his secret identity. But then again, The Scarecrow doesn't have a secret identity outside of the Nolanverse...and a goduncle wouldn't share their last name...You know what? Never mind.
 * Not sure if this is what you mean to say, but the Scarecrow does in fact have a secret identity outside the Nolanverse; he's been Jonathan Crane in all of the media in which he's appeared.
 * How about Ichabod Crane?

The Terwilliger family from The Simpsons is the Alternate Universe Counterpart of the Crane family.
Robert and Cecil are Frasier and Niles' Evil Twins. Whatever happened in the Simpsons universe that caused an ancestor of theirs to have a father named Terwilliger instead of Crane is the same thing that led to them becoming insane and/or criminal, and what made them aspire to be clowns rather than psychiatrists.
 * I actually just assumed this was a given.

Daphne wasn't actually acting in "Moon Dance".
She just thought Niles was saying all those things and playing up the eroticism of the tango in order to impress the guests, so she pretended she was acting too, not knowing that Niles wasn't actually acting. Niles fell for her hasty cover story, and of course pretended he was acting as well, apparently confirming Daphne's assumption.

Daphne was secretly in love with Niles for as long as Niles was secretly in love with Daphne.
They were both Oblivious to Love and both suffered from Cannot Spit It Out and both thought the other was not in love with them. It's just that Daphne was better at hiding it from the audience than Niles, and unlike him, never got into discussions of her feelings with anyone else (possibly because of Maris). She could have interpreted all of Niles' uncontrollable flirtations and double entendres the same way the audience interpreted Daphne's "oblivious" double entendres and accidental flirtations, and pretended they went over her head because she was so tempted by what she thought were innocent slips of the tongue on Niles' part that she couldn't handle joking around with him about them.

Frasier takes place in The Sandman universe.
When Martin and Niles argue over who got closer to Death, Martin claims that he kissed Death on the lips before hastily adding that it was a girl. In The Sandman, Death is indeed a girl.

Roz DID want to have a threesome with Niles and Daphne in "Proxy Prexy"
When she misinterprets what Niles says to mean they're inviting her to a menage a trois, Roz is initially dumbfounded, but after a few seconds, when Daphne accidentally perpetuates the misinterpretation by saying "well, do you have anything to do this afternoon?", she responds with a fairly curious "well...noooo...but..." and was extremely embarrassed and defensive when they kept teasing her about it afterwards. She definitely was interested.

Daphne eventually murders Niles and commits suicide
In one episode a psychic apparently told Daphne she'd end up killing her family and herself (and the psychic was right about Daphne moving to Seattle). After all, Daphne does act pretty odd at times. Also, she worked for a psychiatrist for ten years and then marries another one - all those references to emotional instability evoked her own. She seems to lose a lot of her personality after marrying Niles. Then there was the whole thing about Niles idealising her as the "perfect" woman (talk about pressure!). She also came from a family with a substance abuse history (which is statistically more common in people with emotional problems). Besides that, a sad upbringing doesn't help (and she mentions it throughout the series, often with a passive-agressive attitude). Maybe this explains her wavering accent - perhaps the instability in her voice reflects the instability of her emotions. She seems to repress a lot - one never sees her lose her temper the way Frasier, Martin, Roz or even Niles do. The only outburst that's really poignant is when she smashes the vending machine at the hospital (and that's a real healthy way to express yourself!). If she keeps repressing all this pain from her childhood and adulthood, it just builds and builds. Until one day she snaps in order to let it all out in one striking catastrophe.

== Captain Morgan Bateson of the U.S.S. Bozeman is a distant descendent of Frasier's. == It's just Identical Grandson taken to extremes. It seems that the Crane family's tendency towards professional excellence did not die off, as Frasier's several-times great-grandson became Captain of a Soyuz-class starship. On the other hand, the Crane family's tendency to get oneself into huge disasters didn't die out either, as he got trapped in a time loop for 90 years.