I done more reasearch on FNaf (Via youtube) and I've taught myself a few things
Phone guy's death: If you had played FNaf you'll know this but Phone Guy is some dude who left a voice mail at the start of the game i think, he explains a bunch of thing then a banging is heard on a door and Foxy the pirate fox animtronic is the only one who bangs on the door, then a moan is heard, Bonnie the rabbit animtronic and Chica the chicken animtronic moans because they were singing animtronics and their voice boxes would be damaged whilst being used alot then a little tune, this is heard before Phone Guy's call cuts into static, Freddy Fazbear the musical bear animtronic is the only one who plays this tune when he's in the kitchen or the power goes out, some have said Phone Guy was been killed by all if the animtronics because there was a sound by every animtronic but thing is, if Foxy was banging on the door it would be impossible for Bonnie/Chica to get into the room and if Freddy played his tune, the power must have gone out but Phone Guy's call didn't end straight away, he might have been using a battery powered device but battery power doesn't make a phone noise when a call starts, what the main conlusion is that Foxy was banging on the door because it was closed whilst Phone Guy was looking at the kitchen that Freddy would be in, making his tune easy to be heard through the call and Bonnie or Chica must've got in and killed Phone Guy.
Where's phone guy's body???????: There is two famous things, 1, Chica's suit this is because if you look closely into Chica's mouth you can see an extra set of teeth but that may be because of her frame that is inside her suit, 2, a freddy suit, I find this the most trustable because of Golden Freddy, Golden Freddy is a empty animtronic suit that can apear on a poster then in the room the player/you are in, if you look closely at Golden Freddy's eyes you can see two white dots in his eyes and over his eye sockets are hand prints, like someone was trying escape from being put into Golden Freddy's suit, Phone Guy might have been stuffed into Golden Freddy.
Why does Foxy hide?: If you have played FNaf, you might have noticed Foxy hides in pirate cove, from what I've listened to, it's against the rules to have a animtronic with exposed frame, Foxy's suit has alot of rips, on the chest but all of his legs have exposed frame, possibly the reason Foxy hides is because the other animtronics want to put him into another suit, Foxy hides intill running god speed to the room the player/you are in and if the door closed, he bangs on the door and if you don't answer he goes running god speed back to his hiding place in pirate cove.
The bite of 87: It is known that Foxy caused it, a child was taunting Foxy and getting closer to him then the child got too close and Foxy bit off the child's frontal lobe, the child may have died or the child may have lived, who knows?, after the bite pirate cove was closed down to prevent the bite from happening again and through that Foxy began to ware down into the mess he's in
Story: Freddy's pizzaira is haunted by five children, four possibly haunt the four animtronics, as I listened to, two children were led into a back room by someone who was dressed as Freddy Fazbear and killed the children and it got repeated again only with three childen, completing the five children circle of ghosts, the fifth children roams around the pizzaira, the animtonics are maybe 'malfuctioning' because their systems are possed by the children and heading to kill Mike (the night gaurd/the person you play as) as a revenge on humanity.
That's all I have for now, I'll post more if I find out more