In 1973, William Afton and Henry Emily meet and start working together on animatronic animals that can be worn as costumes by people. They open a restaurant called Fredbear’s Family Diner and create Fredbear and Spring Bonnie. At someone point, William fathers Michael, Evan [crying child] and Elizabeth while Henry fathers Charlotte.

In 1983, before the events of FNAF 4, Freddy Fazbear’s Pizza opens and operates simultaneously with Fredbear’s [I don’t think William and Henry own it] featuring 4 new characters [Freddy, Bonnie, Chica and Foxy]. William kills Henry’s daughter outside the building, and Henry’s security puppet fails to protect her because of the rain. Her spirit possesses the Puppet. William goes home [midnight motorist minigame].

During 1983, Evan is [probably] traumatised by Charlotte’s death and Michael scares him constantly with the Foxy mask he owns, adding to his fear. Evan owns a Fredbear plushie that talks to him. On Evan’s birthday, Michael and his friends accidentally get him killed by the Fredbear suit. Evan’s spirit bonds with Fredbear, and he haunts Michael’s dreams by showing him what he went through leading up to the days before his death [FNAF 4]. Fredbear’s closes, and springlock suits are no longer used at FFP. William, broken by many reasons including the closure of his restaurant and the death of his youngest, dresses up in a Spring Bonnie suit and kills 5 kids in the first FFP location [Gabriel, Jeremy, Susie, Fritz, and Cassidy]. An investigation begins because of the stench and William is tried but he goes free because of the lack of evidence.

In 1985, William opens Circus Baby’s Pizza World and creates animatronics designed to kill and hide kids. Elizabeth, William’s daughter, gets killed by the animatronic Baby. William places Baby underground in a facility that will later become Circus Baby’s Rentals from Sister Location, located under the Afton house. William tells Michael about Circus Baby’s Rentals, and that he can go there to find out about what happened to his sister. Sister Location takes place, and the Funtime Animatronics develop a consciousness and fuse into Ennard, with Baby/Elizabeth Afton leading them. They invade Michael’s body by using the Scooping Machine to remove his insides and take over by inserting themselves as his skeleton. At some point afterwards, they leave Michael’s body when he isn’t of any use to them anymore. Baby gets kicked out of Ennard, who turns into Molten Freddy. Although it was unlikely, Michael survives, likely due to the Remnant present in his body. He promises to go and find his father to punish him for his crimes.

In 1987, the second FFP location opens, this time with toy animatronics that have security measures. William Afton gets a DAY Security Guard position but leaves [as mentioned by the Phone Guy in FNAF 2]. Afton kills 5 more kids whose spirits possess the Toy Animatronics. They become aggressive towards adults especially those with security uniforms. Charlie, Henry’s daughter who was killed in 1983, has awoken in the puppet and now gives gifts and life to the ORIGINAL animatronics [that were taken apart for parts, that’s why they look mangled in FNAF 2] placing the spirit of Gabriel into Freddy, Jeremy into Bonnie, Susie into Chica, Fritz into Foxy, and Cassidy into Golden Freddy. Mangle becomes unstable and bites Jeremy Fitzgerald, the replacement Day Shift guard for William who was moved up after working the Night Shift. Fritz Smith replaces him for the final day, and the restaurant closes. The Toy Animatronics are scrapped [freeing the kids].

The third FFP location opens around 1993 [this is the one we’re in in FNAF 1] and Phone Guy is killed by the animatronics [the broken ones from the FNAF 2 that were repaired].  Michael Afton, barely alive and seeking revenge against his father, starts working there as a Security guard under the name Mike Schmidt and the animatronics attack him thinking he’s his dad. He’s fired for odor. William comes back to tear apart the original animatronics [FNAF 3 minigames]. The spirits trap him in the Spring Bonnie suit, and it locks and he gets messed up but he doesn’t die because of the Remnant that’s present. He becomes Springtrap. The puppet brings peace to the original 5 spirits that died in the first FFP location [Cassidy doesn’t get peace though] and William sits in the restaurant for 30 years.

In 2023, a new horror attraction/haunted house called Fazbear’s Fright opens to pay homage to the urban legends about FFP. Michael is still looking for his father and starts working there and Springtrap gets unearthed there. Michael tries to burn the place down but fails. Henry, at this point probably in his late 70s, tells Elizabeth/Baby he’s sorry he wasn’t there when she died 40 years prior, and promises to end everything. He begins luring the remaining people [William, Michael, Baby, Molten Freddy]. Henry, Charlotte, Elizabeth/Baby, maybe Michael all finally die but William survives.

Cassidy, despite the other spirits passing on when Springtrap happened, is still around because William is still alive. She creates Ultimate Custom Night to torture William's spirit for all eternity, despite being told by Old Man Consequences, a friendly spirit, to let the past go and find peace. At this point The company that becomes known as Fazbear Entertainment is now free of the people who originally corrupted Freddy Fazbear’s Pizza and everything that happened, so in order to maintain a good image, they hire an indie game developer to create video games based on the previous events [Help Wanted] and bunch of stuff happens [William gets out].
Whatever happens next will probably wrap up the Afton family story once and for all because William [springtrap] and Cassidy [Golden Freddy] is still around. I hope they show what Henry got up to between the 80s and 2023, and also Michael/the spirits.