1.FNAF
Fan Theories: The Bite Of '87
Phone Guy mentioned “The Bite of '87,” in which someone was attacked by an animatronic and lost his/her frontal lobe.
This event is why the animatronics' movements are restricted during the day.
A lot of theories have popped up around which character was responsible.
Foxy is because he has an out of order sign in the pirate cove, also because he seems to have the sharpest teeth, and he has a dislocated jaw.
Freddy is because he has handprints on his face rumors say that the handprints match the placement of Freddy's hands on the poster of him ripping apart his head however, while the position of the hands does match with the handprints Freddy only has four fingers, and the hand print has five. Golden Freddy is because he has the same handprint marks as Freddy.
My theory is that is was Foxy as said above foxy is the only one out of order.
And it could not be Golden Freddy because he's an empty suit and because he was involved in “The Bite of '63” but that a topic for another blog.

And that's the lore and thories for FNAF but if I find more info about the lore and theories I will put them in the comments below, also I'll be posting a blog of the Lore and Theories of FNAF2 soon.

Bonus:
Questions About FNAF1

1.Who do you play as in FNAF1?
Answer:You play as a Character named Michael Afton, you are the son of William Afton known as:“Puple Guy”, and brother of “The Crying Child”.

2.Who is “Purple Guy”?
Answer:“Purple Guy” is a person named William Afton, he is apparently the one responsible for the missing children.

3.Are the animatronics evil?
Answer:No they try to kill you because they think you're “Purple Guy” because you're wearing the exact same security suit as him.

4.What order is the FNAF timeline?

Answer:FNAF4 was “Fredbear's Family Diner” which is the first location,

FNAF2 is “Freddy Fazbear's Pizza” and the second location,

FNAF is also “Freddy Fazbear's Pizza” and the third location,

FNAF SISTER LOCATION is “Circus Baby's Pizza World”,

And FNAF3 is the “Fazbear's Fright The Horror Attraction”.

so it would be:

FNAF4,

FNAF2,

FNAF,

FNAF SISTER LOCATION,

FNAF3.

5.Does “Security Breach” follow the same story as the other games?
Answer:No it sadly does not there's some similarities but no because Scot Cawthon retired they changed the story completely.