WMG / American Dragon: Jake Long

Jake's grandmother was a member of the Huntsclan
In the first episode, when Jake notes how hot Huntsgirl is, Lao Shi warns "Grandpa has been there." We haven't heard anything about Jake's grandmother, so it's plausible that Grampa keeps silent about her - and discourages Jake's romance with Rose - because things between Grandpa and his Huntsclan girl eventually turned out very, very badly.
  • I believe you are sort of correct. But Disney higher ups said no to that.
  • AFAIK, Disney said "No" to Chang being Jake's grandmother. Producers Eddie Guzelian and Matt Negrete said that the issue of Jake's grandmother would have been dealt with in the third season, if it had come to pass. At one time, there was a plan to reveal that Jake's grandmother was killed, and so Jake would seek revenge, but was dropped early on. Still, it doesn't rule out the theory.

Lao Shi is a barefooter.
In Season One, we mostly see him with sandals. A few times we see him barefoot indoors. But in Season Two, he seems to go barefoot outdoors as well. That's another reason why he wears a robe, so no one can see he doesn't wears shoes. His foot fungus seen in "Old School Training" is either the result of being barefoot or the reason why he goes barefoot.
  • Er... The first episode of season two showed him slapping Jake with a slipper he promptly put back on his foot. I'd say it's Jossed, at least for that season.

Yang Jake would be Dark Dragon's pupil in Season Three.

Right after the series finale, the Magical World was exposed by an Alien Invasion.
Characters from both American Dragon: Jake Long and Kim Possible made an appearance in Lilo & Stitch: The Series, so we can consider them part of the same continuity... And right after Jake's travel at Hong Kong, Kim Possible had to deal with the Lowardian assault on Earth. If the dragons didn't come out for that...

The Huntsman was half-blind but didn't want to admit it.
During the second season he never noticed that the dragon Rose supposedly slayed at the Academy was in fact the American Dragon until #88 and #89 didn't flat-out told him that, and was later convinced it wasn't when Rose brought Jake's moulted skin, without noticing any difference. Also, he somehow failed to notice that the American Dragon was identical to the Dragon that kicked him in a pit with a giant crab monster years earlier, triggering his deep hatred for dragons and deepening his then-highly pitched voice (thanks to a bit of Time Travel). Either he's an idiot, or his sight is so low he's pratically half-blind, and he will never wear glasses.

The Huntsclan were originally allies of the Dragons.
The first Huntsclan members (who probably weren't called the Huntsclan, but whatever) were human warriors that aided Dragons against evil magical creatures before The Masquerade set in. They were gifted with power from the Dragon they partnered with in the form of a dragon-shaped birthmark that passed down through their bloodline and made them stronger when fighting with their chosen dragon (like Pactios in Mahou Sensei Negima!). As the Magical World faded into hiding the humans felt abandoned by their partners and gradually turned into the Huntsclan; they still drew on the power of dragons through the trophies they took from them like the skull helmets all full Huntsclan members wear, though this was a weaker and perverted use of the relationship. They kept track of the bloodlines so they could steal infants like Rose when they manifested the mark, now sincerely believing it was their destiny to kill dragons instead of being partners with them. Rose's relationship with Jake reopened the original partnership and explains why she can handle multiple Huntsclan members and fight the Dark Dragon to a stand-still.

The Huntsman really IS Rose's uncle.
Not only was one of Rose's parents is related to him, s/he was also once a Huntsperson. My guess points to Rose's mother. She and the Huntsman were very close, and their family were members of the Huntsclan and a very high-ranking and influential class. But then Rose's mother began to think their ways is wrong. The Huntsman was shocked to hear that and tells her never think that again. She herself fell in love with a Dragon she was chasing. The two have a secret relationship like Jake and Rose. But the Huntsclan soon finds out and ambush him. Rose's mother was devastated to find her lover's dragon head mounted. The Huntsman was furious of his sister's transgression which shamed their family within the Huntsclan ranks. Realizing there's nothing left for her in the clan, she decides to defect (a move that's considered treason and punishable by death), changed her name and began a new life. She eventually meets her future husband who's in the dark of her past. After many years, the Hunstclan was able to find her upon her pregnancy, which the Huntsman handled personally by taking Rose to raise her as a Huntsgirl to make up for her mother's shaming of the family. As far as the Huntsclan is concern, Rose's mother is dead to them. She'll likely approve of Rose's relationship with Jake because it reminds her of something she once had that could have grown.
  • Alternatively, both parents were slayers who left the Huntsclan to start a family and had to leave the Huntsclan because slayers who start families are believed to become soft and the only reason it's not completely discouraged is because someone needs to make the next generation. Rose's parents just pretended to think Jake was delusional so they'd rid of him without Jake suspecting. That explains how Rose had the fighting skills. She needed to have the training. Huntsboys 88 and 89 disprove Jake's theory of being a "natural" just for having the mark.

Spud's family are actually wizards.
He was shown having magical potential being able to use Panderis' wand, his grandfather knowing how to seal away the genie in Taranushis Chalice and also telling him stories about the mermaid city

Rose never had a sister.
It only appears that she did because You Already Changed the Past. The "twin sister" is actually the alternate Rose created by Jake's wish.

The Oracle twins didn't get redesigned
They just tried to differentiate themselves. They dyed their hair and Sara began wearing eye contacts.

Jake's true form is a dragon
He's just raised as a human.
  • Confirmed. It's revealed in the episode "The Rotwood Files" Jake's true form is that of his dragon form, because Professor Rotwood is shown to be in possession of chemicals that can transform dragons back into their true form.

Rose's parents moving to Hong Kong wasn't a coincidence
Following up the above theory that they were Huntsclan members who left the Huntsclan to start a family, they went to Hong Kong to slay dragons attending the reunion but they gave up when Rose told them of a boy claiming to be a dragon who knew she's a slayer.
  • Possibly, Word of God is that had there been a third season, Rose would've moved back to New York City.

The dark dragon is a corrupted Jake from the future
  • Jossed

Before finding out he was a dragon, the Huntsman liked Jake
I mean, as far as he knew he was a nice if eccentric guy who was making his adopted niece happy, and went to console her when her date dumped her at a ball... And the Huntsman had some form of paternal affection for Rose. Then he found out who he really was and that he had 'corrupted' his niece...

Dragons have influenced kung fu, and later adopted the very style they influenced
Some kung fu styles imitates animal movements... And two of them imitate dragons. The Southern one, being more attentive to chi use, was later adopted by the dragons themselves and adapted for use by actual dragons.

Rose's subconscious is the reason #88 and #89 survived and she herself was nearly killed by the skulls
Due their incompetence she couldn't help but not consider them actual members of the Huntsclan, so they were spared. At the same time, she still considered herself a member of the Huntsclan... And had Jake not made his wish, she would have been killed.

Jake is actually paid for his job, but can't actually use his pay yet
Because, being dragons, he's paid in gold, gems and jewels, and the only guys that wouldn't balk at him showing up to sell it for cash are Fu (and nobody would trust him with that much money) and a Leprechaun he knows he can't trust. He probably doesn't even know about that since he wasn't whining over it when he complained about the lack of money before getting a job working for Brocamas.

Jake's first season form was because the Dark Dragon was unofficially the "first" American Dragon.
Basically the Dark Dragon is native to North America but due to his actions, the Dragon Council doesn't consider him to be an American dragon. However his status does effect things; Jake and Haley look American at first because the Dark Dragon is technically the first American Dragon but the world acts on the principles of Fisher Kingdom and once the half-Chinese Jake has been in his protector role long enough, his heritage affects his form, setting a precedence for dragons in America to reflect the "melting pot"/"salad bowl" nature of the country's citizens; given Haley is Jake's sister, her form changes in a similar fashion though because in America, there's some personalizing of forms, she doesn't match him exactly. It's just that no one realizes this in the canon time-frame since it's the first case of it. It's likely there are native dragons in other countries that influence the forms of the protector dragons and if other countries suffered a "Dark Dragon", they might go through a similar process.

The Dark Dragon Refused The Call
We've seen what being a dragon does to someone. It drove Jake's sister into a complete wreck in less than a month. It's hell on Jake. People don't choose to become dragons. They're born into it and stuck in the role unless they screw up sufficiently. Maybe the Dark Dragon saw what this job did to people and refused the call. Maybe he decided that this was basically a caste system, and they were born into and stuck doing a thankless job nobody else wanted and suffering for it; and half of the job just existed to maintain a masquerade. The Dark Dragon is considered evil by the council because he rebelled against the system, and he's considered by the leaders to be more dangerous than the Huntsclan because he's the only one with the will and power to overthrow the system.