In the final minigame of fnaf 4, four kids are seen carrying the kid you play as towards Fredbear, and through him into the mouth of Fredbear, making him bite the child. Then we all know the Purple Guy murders four children, the fifth child is probably the child you play as in fnaf 4 who shortly died after the killings during fnaf 1. Btw, the easter egg that I think appears on the TV that says “Freddy Fazbear 1983” or something like that, I THINK it means that Fredbears Family Diner was FOUNDED in 1983 and that the bite DID NOT occur in 1983. Fnaf 2 might of took place shortly the second location after Fredbear’s Family Diner was closed, and fnaf 2 took place in November which is late 1987.
So I think that Purple Guy murdered the Four children after he found out they caused his sons death, his son being the kid the four children have bullied. Why else would he randomly attack four kids? Purple Guy could be the kids father and work with Fredbear Co. since the kid is forced to go to Fredbears with him even though it is clear he is afraid of the place. I also think Purple Guy is Phone Guy in fnaf 2 and 1 since in the Night 3 Minigame if you walk back towards the red door you can see Purple Guy helping someone get into the SpringTrap costume. Who else knows a lot about the SpringLock suits? Phone Guy! As proven by the phone calls of the original Phone Guy in FNAF 3.
So in conclusion, I think the kid you play as is afraid the Fredbear’s Family Diner and since he is his brother pulls pranks one him by scaring him with the Foxy mask, and his father brings him to work even though the kid is clearly scared of the place, later on four kids bully the child and throw him into Fredbear\s jaw in 1987, NOT 1983! And Fredbear caused the bite of 87. Purple Guy/Phone Guy finds out what happened to his son and murders the four kids who later possessed the suits, then during fnaf 1 the child later dies do to his injuries and possesses Golden Freddy/Fredbear since he was bitten by Fredbear back in 87. Purple Guy then goes crazy and destroys the animatronics to find his son or to get rid of the evidence. That’s all I think for now.