Anybody notice how when the puppet has to "give them life" he turns them into animatronics, specifically the older ones, is this hinting at something?
My theory goes as so,
Way back at the beginning, (FNAF2) the animatronics were introduced in the new style of restaurants.
The puppet was possessed (or hijacked) and went on to change the rest of the animatronics like him, reprogramming them to kill everyone.
Because of this, the diner shut down in FNAF2
They made a reboot of the diner in FNAF1, and simply fixed the old ones due to the old budget. Because these were never programmed again, they come to kill you too. Evidently, when the phone guys says "I'll probably take the next shift, it will be safer if I become the night guard" hence the phone guy in FNAF1.
Now some say, where did the original suits come from? The original suits came from another diner the phone guy in FNAF2 doesn't mention the name of. He says, the "old place", which may or may not mean another completely new one. The bite of '87 can also be in the same year. The reboot could've easily happened during the same year, iirc, it said 10/__/87, giving it two months to start over, so meh.