In my version of FNAS, most of the characters are redesigned to look less like the original FNaF characters(such as Mario losing his Bunny Ears, Tails losing the Pirate getup, etc.). Clone Yoshi and the nightguards are the only fully original designs(which is why they look the worst lmao).

If I ever turn this into a game I'd give the ceiling vent a bit more of a gameplay function, functioning much like in FNAS 1 2.0, except you would be able to fend off characters that take that route to you. There would also be a few other new mechanics I would throw in to give character more unique behaviors than just heading to your doors.