This is the Five Nights at Freddy's Timeline by Ice. Note: This is not canon, however it has strong evidence pointing toward its canon-ness. Please don't start saying things are fake, because its a theory, however if I have an error please tell me. Shall we begin?
GEN 1 - Fredbears Family Diner
Fredbears Family Diner was opened sometime in the 1980s. I'm going to take an educated guess and say 1983. This was the first location known in the timeline. It is a very small location compared to the later ones. In the begining the owners of Fredbears wanted to make something unique to their location. They wanted to add springlock animatronics to make wearable AND they wanted them to be animatronic suits at the same time. With this concept they made 2 animatronics: Spring Bonnie (Springtrap), and Fredbear (Golden Freddy). Then, Fredbears Family Diner was created. There was mostly nothing to do, other than eat cake and watch the animatronics perform, but it was still pretty popular. After the launch of Fredbears Family Diner, a certain kid went there. This kid was lost and couldn't find his mother. Shortly after, a man in a purple suit murdered the kid. The people were shocked at first, however they believed it was due to the parent, so they just ignored the death. This kid posesses the soul of the marionette eventually, but right now he is the somewhat ghost of the kid. Fredbears Family Diner began to grow in popularity, so much so that they had to make a new, bigger location. This resulted in:
GEN 2 - Freddy Fazbear's Pizza
Freddy Fazbear's Pizza. They decided to keep the springlock idea and add more animatronics, as well as give a new redesign for the originals. This created: Freddy Fazbear, Bonnie the Bunny, Chica the Chicken, and Foxy the Pirate. They got more workers to work at the location, more popularity, etc. and this is the same era were they hire phone guy. Phone guys role in Freddy Fazbears Pizza is to instruct workers on how to use the springlock suit. The original Freddy Fazbears Pizza, actually has the same layout as FNAF 1, but I'll get to that later. Moving on, this man in a purple suit strikes again, killing 5 children, stuffing them in suits. Shortly after these deaths, the children possess the suits they are in and the ghost of the kid from fredbears diner gives them life as well, so they can at least expeierience an afterlife, and also so he (the kid) can build an army to get revenge on this sick bastard who killed all these kids. After the deaths, and reak of the place, it closed down. Then in 1987 they open up the place again. Phone guy now teaches security guards how to survive their shifts. The children are still angry and then low and behold
GEN 3 - New and Improved Freddy Fazbears Pizza
The New and Improved Freddy Fazbears Pizza opens. The children are posessing two suits at once, to get double revenge. And the kid posesses the Marionette suit. He is very impatient, and if he doesn't here his lullaby he will kill you. The security guards where purple outfits, making it easy for the souls to confuse them for the murderer, so they will automatically take them as a target. Shortly after the opening, another incident happened with an animatronic. The Mangle bit a persons frontal lobe off because of it being angry. Mangle must've been so angry of kids stomping on her that she had enough and she bit a persons head off. This lead to the new animatronics being scrapped. Shortly after, purple mans burns down the restraunt. It is 1993 and Fazbear Entertainment is low on money and they want to open a new restraunt, so they take the old restraunt from GEN 2 and open
GEN 4 - Freddy Fazbears Pizza (again)
Freddy Fazbears Pizza, for another time, hoping to gain more money off of this one. They took the old animatronics designs (except they removed the springlock) and the original 4 came back resulting in the re-opening. The children once again posess the animatronic suits, but the 5th one lingers and haunts the security guards, in his golden freddy suit. The purple man decides to take them on himself, and applies for security guard. Yes, the purple man is indeed Mike Schmit. Mike gets haunted from the murders he did, like hallucinations saying Its Me, because it haunts him to know that HE is the one who did this. The animatronics believe that Purple Man is the Phone Guy, but they were wrong. Once they figured this out they knew for a fact Mike Schmit did it, so they became furious and try their best to stuff this man like he did to them long ago. After Mike finishes his job, he does his final plan: Dismantle the animatronics so he wont be haunted anymore. The shadow of fredbear (Shadow Freddy) or the Ghost of Fredbear wants the children to defeat Mike, so he tells them to follow him, but shadow freddy didn't know that the animatronics can't see backrooms. But he still attempts to make them go into the room. The 5th child starts catching on and he takes off his suit, making it able for him to go into the backroom. That scares Mike, because he didn't know that was possible, so he runs and hides in the springlock suit, knowing he is safe, but he didn't know how to work it so he died. The children have finally completed their task, so they can finally move on. Purple mans soul lives inside of the springlock suit, and he wants to still kill the children, so whenever he hears anything child related, he goes after it. Purple man wants to kill everyone, little does he know: He can't.
Hoped you enjoyed my theory :3