Thoughts so far:

-Harvest?

-Oogie dynamics:
[list][*]Trickster's mother was a prostitute. She loved them, but was very hands-off in her parenting, partially to keep them from the nature of her job. This has the caveat of the three not really having much in the way of moral guidance, particularly because she taught them (out of necessity) how to pickpocket.
[list][*]"Go play until I call for you/this is important, do it."[/list]
[*]One of her Johns made her cry. While the trio doesn't know in what capacity, they feel turnabout is fair play. Shock masterminded the whole thing with the expectation he'd get hurt, and wrangled her brothers into helping her because it'd be funny. They didn't expect the man to break his neck, or to be spirited away by the boogeyman for it.
[*]They were forced to forget their old lives as a form of control, but respond to them same style of hands-off parenting. They bring Oogie things to eat and perform occasional tasks; they otherwise do what they want.[/list]

-Carmilla and Lillith:
[list][*]Formal, polite, loyal to the Pumpkin King. They're identical twins, but different personality-wise. Like her namesake, Carmilla is a lesbian, while Lillith is bi.
[*]Carmilla is also the only person in town who can rival Shock as the top bitch. Where Shock is calculating, devious, and mischievous, Carmilla is cold and polite.
[*]Lillith is a bit stand-offish, but much kinder than her sister.[/list]

-Agatha is still the token straight. She doesn't like trouble, but if there's an opportunity for subtle vindictiveness, she'll take it. Of all the teens, she's probably the closest one to a sweetheart. She's also probably the most responsible one.

-Band:
[list][*]Lock formed The Devil's Pitchfork as an outlet. He's going through a rebellious teen phase, and this is one area he has complete control over, since he can't overpower Shock, and he's tired of being bossed around by her, since after Jack, she's the closest thing to a parental figure the trio have.
[*]Starting band: Lock (lead guitarist, secondary vocals), Shock (lead vocals), Barrel (drums), Carmilla (secondary vocals, synthesizer), Lillith (theremin), Harvest/Aod/? (xylophone).
[*]Shock and Carmilla butt heads over the lead position. Carmilla has technical singing training, and is better in many aspects, but Shock can shriek and screech in different ranges, which Lock needs for his band. Also, she's his sister and he has an incentive to keep the peace so his band can actually function.[/list]

-Misc Halloween Town:
[list][*]Harvest(?) and Behemoth are bros because of their pumpkin patch work.
[*]The main Halloween Town musicians are fine with the kids creating their own band, as they aren't trying to compete. Halloween Town overall is supportive one, because many of the kids are doing something creative between Halloween prep, and two, if Lock, Shock, and Barrel are occupied with practice, they aren't causing trouble elsewhere.[/list]