Five Nights at Freddy's is one of the few franchises were logic and inconsistent could be answered by either "the creator didn't think about it" or "the creator thought it looked cool".
How tf do the eyebrows on the animatronics work???
Cause like they can make angry expressions which imply they have some kind of way to spin in a circle.
But then there's image 3.
So....
I love when you put Ollie and Bendy together you can clearly tell how different they both are by just their designs. The voices of DaGames fit Bendy and Skull from JT Music practically fits Ollie as well.
Papyrus says "NYEH HEH HEH" and has all caps while sans uses lower case and is honestly just chill. I'm not surprised that they were the to go choices.