All Caligulans are Bisexual
At one point, Green mentions that if two guys are lost in the wilderness together, it is assumed that they're having sex. This indicates not only a lack of homophobia, but a widespread assumption that anyone is willing to sleep with someone of the same sex. Clearly, though, Caligulans are not all gay, as many are seen in heterosexual relationships.
Maxwell Wevers is based on Pegasus
He's got long hair that could be mistaken for white, he's the CEO of (or at least highly placed in, I'm not sure) soem company, and the author has already stated that Lette's design was based on Kaiba.
Maxwell Wevers will eventually get a girlfriend who is an Expy
of Cecilia/Cyndia or Ishizu/Isis
Jessi-sama has stated that she likes both Roseshipping and Sightshipping. While it's true that none of the other expies were romantically involved with counterparts of the originals' love interests, the others don't have as set love interests.
Most Caligulans are Bisexual
Jessi-sama jossed the all Caligulans are bi theory, and gave examples of ones who weren't. That doesn't rule out that bi is the most common sexuality, like straightness seems to be in humans.
Future characters will be introduced, who will be more Yu-Gi-Oh!
She's done it before, she may do it again.
- Semi-confirmed, as of the 2012 Memorial Day page-Lette has an "Uncle Joey". He's dead, but still.
- Also, Stella's hubby/baby daddy Adriano (from Parenthood Prep) is Atem.
- Wasn't Skyla also Atem? Are there two Atems running around?
- No, Skyla was just short enough to be Lette's cosplay partner, that's all.
- But she's the Pharaoh of Awesome.
Rose's friend Kitty will end up going out with Stud
Kitty's one of very few women who treat him like a person, and he's currently staying with her.
Dahlia is based off of someone from Yu-Gi-Oh!
Dahlia specifically denied being based on the Dark Magician Girl (I assume that's what DMG stood for). She never said she wasn't anyone else.
Law Of Purple will eventually have a whole pantheon
We've already seen Lette, the Goddess of Awesome, and Jay, the benevolent Egyptian godess of localized supermarkets.
- Do the extra-dimensional dragons count?
Alicia Wyrd will find out about Jel and Max, and go ballistic.
Thae lady drove away her next-door neighbor because the woman was lesbian. She won't react well when she finds out her daughter is dating another girl.
Lette's dragon mark's indistinctness is relevant somehow
It doesn't look like a dragon the way Blue's and Daimon's do. Also, it's apparently a birthmark, where the other two are referred to as tattoos. And we know it's not that it isn't a dragonmark, because we saw Lette talking to her dragon.
Red's Wardrobe is a TARDIS
It's bigger on the inside!
- Hey, that means the ancient civilization the technology came from would be Time Lords!
- So Ksathra is Gallifrey?
- Makes sense. In forum, Jessi mentioned that the Ksathrans had transcended mortality and become beings of pure thought. That was part of at least one plan the Time Lords had.
Rachel had a neglectful father
She's shown to care very much that Memphis not be a "Deadbeat Dad". Memphis says he knows how he feels about it, which indicates that this is an active thing that she thinks about, not an automatic thing like most people would feel.
He's a captain, and he'll sleep with anyone.
- Well, anyone of the "human" races anyway.
- Wait, how does this affect the "Ksathra/Gallifrey theory?
- No, he can't be. Captain Jack was born in the 51st century.
Lynnah's Gaydar is somehow caused by alien heritage
Several alien races have been shown to have at least minor psychic abilities. Terrans are not one of them.
- Actually, gaydar happens in real life. 
Zefiryn was a member of the royal family
Green says she died the night he and his siblings left. That was the night the entire rest of the royal family was brutally murdered by Silver.
Caligula will end up with a representative government.
Silver's going down, and the Fayses don't seem the type to want the throne. Also, Jessi-sama has indicated a trend towards democracy, in Geist overthrowing Silver's puppet regime and electing the crazy clothing girl president
Caligula will end up with a half-human ruler
Red's the oldest living member of the royal family, aside from Silver, who Jessi-sama isn't likely to let remain a Karma Houdini
forever, and he married a human.
Stella from the Parenthood Prep class is based on Sailor Moon
According to the author's notes, most of the people at Parenthood Prep are parodies. Stella's hair closely resembles how Jessi-sama has drawn Sailor Moon on her Deviantart account.
- Also, her hair clips are a black and a white kitty. This could easily be a reference to Luna and Artemis.
This was the first thought I had when I saw him. He's camp,he's surrounded by floating hearts, and their facial structures are similar.