Dreamfall: The Longest Journey/WMG

April is not only a Shifter, she is also a Dreamer
In the very beginning of the game, April dreams of Arcadia and then "falls" into it and can interact with physical (tree, egg) objects there, just like Zoe's "dream presence" in Dreamfall. This is the only instance in the game that April physically travels to Arcadia without (visibly) passing through a Shift. E.g. in a later chapter, she similarly opens a Shift in her sleep, but still has to wake up and step through it to actually use it. Indeed, her first encounter with the White Dragon (and it was real, since when April revisits the same location via regular Shifting late in the game, you can still see the traces of her previous visit) took place even before April's first definitive Shift with Cortez's help. Unlike Zoe, April apparently doesn't need Morpheus and the Dreamer consoles, either because she is just that freaking badass or because the Divide was much easier to cross that way with the Guardian absent.

April is not in Arcadia in Dreamfall (ties in with the above)
She is in Stark, dreaming of Arcadia. The Darker and Edgier "April" is actually her dream presence, while her body is hooked on life-support in the Vanguard labs, who brainwashed her to prevent her from realizing the truth and waking up. This is also why she cannot Shift to Stark. Thus, she. And she will be a playable character in Chapters, of course.

Kian will turn on his captors and rescue April
Zoe's "saving" of April consisted of facilitating her meeting with Kian near Friar's Keep (when she was captured as a witch). At that meeting, Kian met April under non-hostile terms and she managed to pull him over to her side. Also, Na'ane will redeem herself by coming to his aid and patching up April's wound.

April unconsciously opened a Shift to Stark in the last moment
And will be nursed to health by Emma and Charlie in Chapters.

April needed to be "saved" from losing faith
Thus, Zoe saved her either by helping her regain faith in her destiny (either as a consequence of a Near-Death Experience, or through the believer Kian's influence), or by leading her to her death, preventing from losing faith completely.

April was actually Killed Off for Real
Because she lost faith in her higher purpose and powers.

Helena Chang is Zoe's mother
Helena "knew a Castillo once". She and her company "created" Faith, according to Jeanine Park. The "white lady" said that Faith and Zoe are sisters, and Faith believed her. Helena may have been Gabriel's wife but they divorsed shortly before the Collapse and he claimed she was dead. The Collapse helped a lot, destroying most reliable records and discredeting the rest.

Zoe's mom is really dead
...but Chang knew her and Gabriel and used her stolen genetic code to clone Faith.

Zoe's Dreamer talents created a Recursive Reality
By telling the Vagabond her story in the end, she created a world where she fell into the coma and told her story to the Vagabond in the end.

Rescuing Zoe from coma will be a big quest in Chapters
She was promised to return.

The Undreaming is a living creature
It devours people's dreams, thus it facilitated the creation of the dreamer consoles to put humanity into the state of perpetual dreaming. The living Dreamers like Zoe are like a poison to it because their dreams are particularly strong and hard to devour.

The Undreaming is a force of nature
Kinda like a personification of Ragnarok, it is out to destroy the Balance and the Twin World. Judging by its name, it is the Evil Counterpart to the Dreaming in Aboriginal Australian Myths. This is further supported by prolific allusions to other parts of Aboriginal mythology (Alchera, Eingana, etc.).

The Undreaming is Nothing from The Neverending Story
Both phenomena start destroying reality when people start losing faith in their dreams. Also, the symbolism of towers.

Brian Westhouse is an avatar of the Undreaming
The Undreaming corrupted and took control of his body in the 300 years he was trapped between the worlds, then spit him out into Arcadia. He is also likely to be the one hunting the Kin and is the real identity of the Azadi Prophet.

Brian Westhouse resisted the Undreaming
So it just dumped him into Arcadia, leaving him exhausted and devoid of dreams and inspirations, so he turned into a regular drunk. He got over it by the time of Dreamfall.

The monks sent Westhouse to the Undreaming on purpose
If you sneak up on them in the prologue, you'll overhear them talking about it. The only question is whether Chavez/Cortez knew about it, too, or not. If he did, he may have been also possessed by it or hoped that Westhouse somehow keeps it in check.

The "Collapse" was a Cosmic Retcon by the new Guardian
Immediately after April left the Tower in TLJ, Guardian Gordon started fixing the bugs and glitches in the Balance that slipped in during Adrian's "overtime". Those included the removal of magical "technologies" (Anti Gravity, Faster-Than-Light Travel, neural interfaces; all according to the fluff booklet) from Stark and technological "magic" from Arcadia.

The Collapse was orchestrated by secretly-evil Gordon
Gordon is STILL working for the Vanguard and aimed to weaken the Twin Worlds to facilitate their future reunification by deliberately pumping too much magic into Stark. Likewise, technology was pumped into Arcadia, giving rise to the Steampunk Azadi Empire.

The Guardian's Tower fell because Gordon is the last one
The Tower was only necessary for the Changing of the Guard ritual. Since Gordon is the last, the Tower was no longer needed. Alternatively, Gordon is the last because the Tower couldn't last much longer and no new Guardians can be inducted in the future.

The Guardian's Tower fell because Gordon is evil
Either it fell to expose his corruption, or he destroyed it on purpose. Most likely, he still secretly works for the Vanguard.
 * Also, he was way too eager to convince April that the events of Dreamfall have nothing to do with her (not that she needed much convincing).

Gordon is moonlighting
Adrian told April that the Guardian loses all sense of self for a thousand years, becoming a conduit for scientific and magical energies. Gordon, on the other hand, could disconnect from the tower and converse with April.

Gordon is doing a sloppy job
The Azadi have guns and Schizo-Tech in Arcadia, while the Wati have neural interfaces on their dreamer consoles, which is said to have stopped working after the Collapse.

The "heating" steam machines actually collect dreams
They are the Arcadian counterpart to the dreamer consoles and collect dreams to send it to the central storage (the Azadi Tower, which is the counterpart to the Starkian Eingana).

The Chamber of Dreams is a remote storage of dreams for Eingana
A Wati scientist mentions that Eingana seems to store more dream information that it is physically possible. In fact, Eingana is connected with the Azadi Tower and transfers a part of its stored dreams directly to Arcadia. Also, if you recall, the major Eingana malfunction that Zoe witnessed conincided in time with the violent energy eruption that April saw in the Arcadian cave.

The White Mother was the Goddess of the Azadi
She managed to kept their expansionist policies in check until her death, that's why nobody heard of them before her death.

The Prophet is Brian Westhouse in disguise
Westhouse has some unexplained relationship with the Undreaming. He disappears right before April spies on the Prophet and reappears when the Prophet vanishes. Also, if you take a screenshot of the blink-and-you-miss-it shot of the Prophet looking in the camera and adjust contrast and brightness, you'll notice that he looks a lot like Westhouse.

The Prophet is the Guardian Gordon
He is still working for the Vanguard.

The Prophet is the Blue Kin
The White Kin says that she cannot feel the Blue, so he may be in hiding. His apathy in the first game was because he was gathering power and strength for the upcoming reunification of the Twin Worlds, which he now facilitates as the Prophet.

The Prophet is Gabriel Castillo
He is actually the mastermind behind Project Alchera and the Azadi Tower, that's why he played the Disappeared Dad throughout most of the story (as the project entered a critical phase). Like his daughter, he is a Dreamer and can manifest himself in Arcadia as the Prophet. This is also the reason why neither the EYE commandos, nor the WatiCorp security actually harmed Zoe at any point. The only one who truly wanted her dead was Helena Chang, who may be Gabriel's ex-wife and enemy.

Kian is the son of the White Mother
And thus, April's brother. "Alvane" is their real surname. Officially, Kian is Conveniently an Orphan but Commander Vamon noted that he rose through the ranks way too fast for an ordinary "motherless boy" in Sadir. Maybe his mom covertly pulled a few strings for him?

Kian will save April and marry her later
They are obviously set up as a couple and what's better than a classical Rescue Romance to kick-start a relationship?

The White Kin was attacked by Westhouse
He is the avatar of the Undreaming. She is the young but only remaining protector of the Twin Worlds. The rest is Self Explanatory. Also, she was afraid of him upon their first meeting and the Kin recognized her attacker shortly before he made his move.

The White Kin was attacked by the Dark captain who delivered April to her
The captain didn't recognize April as a Wave, yet another Dark person later says that all Dark People form a single Hive Mind, so the captain had to recognize her. He may be either disconnected from the rest (corrupted by the Undreaming?) or an impostor. Either way, it's enough to make him a suspect.

The White Kin was attacked by Guardian Gordon
Either because he is evil, or because he thus restored the Balance (since either Red, or Green, or both were killed in Stark, creating disbalance in favor of Arcadia).

The White Kin was attacked by the Blue Kin
The Blue Kin decided it's finally time to go home and decided to take his relative with him.

The White Kin was attacked by Crow
He was corrupted by the Undreaming in the eight years after April dumped him. And you can clearly hear wings flapping in that scene.

Whoever attacked the White Kin already killed the Blue Kin
That's why she was hiding after sensing his death.

The white lady resides either in Arcadia or between the Worlds
Faith, a resident of Winter, is her only link to Zoe and the rest of the "real world". She has very vague idea what what's happening to both April and Zoe, since all she can say is "go find April, save April".

The white lady is the White Kin
Both are white. The White Kin would want to protect her sister and had a chance of knowing about danger to April.

The white lady is Helena Chang
She knew Faith and wears a labcoat. She was also the only one who could reasonably reveal to her that she and Zoe are sisters.

The white lady is Lady Alvane
She is gray-haired and a "lady". She already helped April once.

The white lady is the Anthropomorphic Personification of Eingana
Eingana had developed her own identity and became a Robot Girl. She had unrestricted access to Faith, ports in Arcadia, and would probably have her own agenda.

Reza was caught and brainwashed using the dreamer console
Reza's last trace is the bloody handprint at the backdoor of Victory Hotel. That's when he was captured. Then Alvin Peats "ate his dreams".

Reza was killed and replaced by clone
That's why "it's not him" in the end.

Reza was a mole from day one
He had everything set up too conveniently: a hidden laptop, a pre-programmed Watilla, etc.

The Sentinel Temple serves as a beacon to those crossing the Divide
When April first arrived to Arcadia, she appeared inside the Sentinel Temple. When Zoe traveled there, she ended up in the caverns underneath the Azadi Tower, which was built on the spot where the Sentinel Temple stood.

Grubbers from the Marcurian caves are related to Bandas
Both live underground use songs for Earth Bending. Na'ane even suggests it in-game.

Grubbers are afraid of April
The only Grubber who would fight her is the Super Grubber in the Necropolis. Normal Grubbers just run away from her, though they would attack Zoe on the spot.

Damien was a Manchurian Agent for Wati
That's why he left Zoe helplessly sleeping in his flat with Wati security hot on his trail.

Vamon's gun was a joke
One of the character designers decided to make a Visual Pun on Chekhov's Gun.

Brynn was the real mole in April's group
After yet another gesture of mistrust from April (during her first meeting with Zoe), he played Judas and ran off to Azadi to rat her out. Zoe "saved April" by keeping Brynn and Chawan inside that shack and preventing him from finishing April off. His battle cry "For Raven!" may have been a codeword for Azadi to recognize him. Or he realized that for Azadi grunts, he is just a rebel and decided to go down fighting.

The static was caused by Faith overloading Eingana
Due to Faith's presence inside it, Eingana couldn't handle all the data it was fed and dumped some of it to the Chamber of Dreams in Arcadia and some, simply onto the Wire, creating "static". Also, Faith herself crawled out of Eingana several times to communicate with Zoe, creating additional disruption.

Faith's death led to the Eingana malfunction that got Peats killed
Peats could only perceive the outside world through Eingana. When he lost it, he was removed from picture.

The Vagabond is God
Because he works In Mysterious Ways.

The Vagabond is the fifth Draic Kin
So that they have the space between the Worlds covered, too.

The released version of the dreamer consoles is harmless
Assuming that Eingana was actually destroyed in DF.