Ohh goodness I honestly dont know BT
Freddy I seriously have no idea…
Chica and Foxy would probably say they’re too mature for it, but secretly dress up in costumes anyway…
Bonnie would probably just put on some Halloween themed suit or something cuz he’s classy like that…
and Springtrap…well he would probably either just throw a sheet over himself, or dress up as a bunny :I even though he’s already a bunny