I think she could get along with Amary!
Amary would be down for any and all types of sweets. There might be a few arguments about who gets to eat what. Anyway. She’d definitely be down for pranks and causing trouble; that was her entire childhood. And she’d totally make sarcastic quips right back at Mallory.
Horror she isn’t super into, but she’s go along with it if that’s what Mallory wants. Or if it;s like a horror movie, she would be spouting drunken comments throughout. Amary also totally gets the bloodthirsty thing. For a while she was on her own killing streak, so she understands. Also, while Amary prefers to be told the whole truth, she understands that sometimes people need to keep things quiet.
I think there would be a bit of understanding between them, even if there were fights. They should get along pretty well.