Ah! Let me think...
I think Airs will be dressed up as a vampire! You know, classic style. Imagine him threatening to suck your blood... Well, and he definitely would enjoy doing that.
B doesn't want to dress conspicuously, but Aris will insist that he does, so he has to wear a classical dress to play the human who has been bitten by a vampire (like a blood servant or something? I saw it in a novel).
C's temperament suits an mummy! But he is too fond of dressing up, so he adds a lot of shiny accessories, looking like a freaky rich merchant covered in bandages and jewels.
D prefers fairy tales over scary things. So he would play Little Red Riding Hood or something. But when he was a child, wearing that kind of clothes was cute, but he didn't realize what he looked like now... Going out would be mistaken for cosplaying Frankenstein.