My take on the lore. Before we begin, remember the following:

1. We know that whoever killed the children used either an empty suit or a suit with the springs snapped into place.
2. Something happened with either Golden Freddy or Springtrap on Day 5 of FNaF2.
3. The order of the games is 2 > 1 > 3.

My timeline theory:

We know that at some point, at least 5 kids were murdered by an unknown man, later revealed to be known as Purple Guy. These murders took place around June of 1987. However, I personally believe there was a 6th kid killed, at the location before the location in 2. This kid's soul possessed the Puppet. After the murders of the other 5 kids, the Puppet placed the souls into the following animatronics: Freddy, Bonnie, Chica, Foxy, and(confirmed in FNaF3) Golden Freddy.(Reference: Death minigame "Give life" in FNaF2). From this point, they began to haunt the suits, attempting to kill any night guard, as they only knew their murderer was a night guard(it's heavily implied that an employee at the location is responsible). It is unknown what suit is used to murder the children, though the only two choices seem to be Golden Freddy or Springtrap.

On Night 5 in FnaF2, we are told there was an incident with one of the suits, and that a position just opened up for the Day Shift. In FnaF1, we are told that, should death happen, a report will be filed once everything is cleaned - in other words, it can be implied that, during Day 5 in 2, an employee climbed into either Golden Freddy or Springtrap, and died from the spring lock failing. The location then covered it up, and thus it was never heard of again. However, since we know one of the suits haunted was Golden Freddy, and we know that they were told NEVER to touch Springtrap, that Springtrap seems to be the most likely candidate for the suit where an employee died.

After the events of FnaF1, eventually, the pizzaria is forced to shut down. Sometime after that, Purple Guy comes back to the location for an unknown reason and begins to slowly destroy the animatronics(which is why none of them could be found for the attraction in 3) by luring the animatronics to the safe room, which they cannot enter. After all this is done, however, one spirit remains not attached to an animatronic: the crying child. I believe the crying child is the child that was attached to Golden Freddy, but his spirit was freed when Golden Freddy was destroyed at some point(it isn't mentioned in 3 at all, and isn't in the death minigames in 3). He makes his way to the safe room, where Purple Guy is lying in wait. Freaked out, Purple Guy rushes into Springtrap and, in his rush, doesn't lock the locks in place, and is crushed. In the good ending, you've actually freed all of the spirits of the kids in the death minigames, and they move on. This ending makes it impossible for the minigames in 3 to take place before the events in 1, as the animatronics wouldn't have been haunted in 1 if this happened before that.

tl;dr

Murders happen before 2 > Employee dies in Golden Freddy or Springtrap on Day 5 of 2; his death is covered up > Springtrap is stashed in the Safe Room > FNaF1 happens > Sometime after 1, Purple Guy returns and destroys the animatronics > Purple Guy is scared into the Springtap and dies > Kid's souls are freed and they all move on.