1st: "Wolfy's Pizza" location in which everything happened is re-opened Fnaf 2 location, and this location is now under new managment, because old owner sold this place to another person. That's why office and some of the rooms are pretty similar to Fnaf 2 location.

2nd: The animatronics are aggressive towards the night guard because Mechanical Lord(Who's name was Krusty and who was performing on the stage with Wolfy, Foxy and Sparky on the stage before he gone into out of order state, and he is out of order because of the accident of course) is possessed by a child spirit who has been killed by the Krusty while he was talking to him, Mechanical Lord can take control of the rest of animatronics which explains why they are attacking night guard as well.

3rd: Sequel is under a question mark