gravity falls au notes/thoughts—
this cherry is the oldest cherry (in her 50s! wow!). her canon story is honestly pretty 70s/80s-coded and plays into the tropes of the religious horror movies of the time, so in terms of dates, it ties in surprisingly nicely with the timeline of GF.
early 1970s: she strikes it out on her own, roaming the country as an artist and exorcist/occultist, passes through gravity falls...then becomes queen of the gnomes. it's actually nikita who becomes the gnome queen, because of course the demon won't reject the opportunity to cultivate power. cherry never would have agreed to it (she can't be tied down now! she has too much to live for!), but because they share a body, she doesn't really have a say in the deal. this goes on, with cherry investigating all the weird stuff going down in the area (while also being investigated by @stnford???) and nikita reigning over the woods, biting heads off birds, etc.
late 80s: one of cherry's little adventures has her in way over her head, and she gets dragged to hell (as in canon). years pass, the quirky artist is missing from GF, the gnomes are out of a queen again, but she was a drifter anyway! maybe she just skipped town and decided not to come back. meanwhile, she's dealing with what is supposed to be an eternity of torture—so she's not aging, has no way to measure the passage of time, even her wounds heal without a trace just to be inflicted again, etc.
late 90s/early 2000s-now: as we know, she eventually escapes, and comes back with white-streaked hair and an eye missing! anyway, this cherry still passes through gravity falls regularly, can be found unwinding at skull fracture, and technically should be gnome queen again, but she's doing her best to avoid that duty.
also, just because i think it's funny and i don't expect anyone to contradict me by rping him, i'm going to say that cherry and jeff the gnome maybe had (or worse, have?) a little on-again, off-again thing, who knows? depends on who you're asking and how much they feel like sharing
ciel: alien. nothing really needs to change except that he was discovered by kamau not in france, but in good ol' gravity falls, which kamau was visiting for research and inspiration for his next novel. he's a funny lil guy for whom disco never died. he's also been in town since the 70s. being a shapeshifter, there's no telling how old he really is. usually seems to wear a turtleneck and bell-bottoms, so if you doubt who you're talking to, that's a clue (;
hansel: also still largely his canon self. he's still a bio professor who researches the paranormal in his spare time. amelia is still his family's science project and cyrille still hates him. he still dabbles in medical care for non-human creatures who can't seek out standard medical assistance, but! he now also picked up a second doctorate (and associated license) in vet medicine solely to inform his practice and make acquiring supplies easier. this part is now canon, btw—i just need to update the carrd!