1-bonnie is blue ( actually purple but nobody cares ) and foxy is red, like sans and papyrus

2-papyrus is every time using a party costume, make sense for an animatronic, use a PARTY COSTUME

3-bonnie in the first game is scott cawthon favorite character, and sans is the favorite character from undertale community

4-bonnie in fnaf 2 is dumb, like sans ( doesn't make sense but I don't care )

5-sans and papyrus are skeletons, so it means that they died, like bonnie and foxy. bonnie and foxy are children souls