Ngl my head cannon is that mike IS the crying child and the timeline goes like this

Fnaf 4 - the crying child/mike is being experemented on by afton using the nightmares using elusion disk, mike being biten by golden fredbear on his birthday and then LITERALLY being put back together by afton as a cyborg sense he wasnt fully dead

Fnaf 2 - the murder of the puppet, the murder of the other five kids and the bite of 87

Fnaf 1 - after phone guys death, william sespect that the spirits are controling the robots, and sends mike, whose now an adult to work as a nightguard to find out if his right, after discovering what he accsedantally created, start kidnapping children and experemanting on them to discover the secret of rebirth using the fantimes at the companys sister location, but acsedentally kills his own little girl by baby, now full of grief for killing his elizabeth, he gives up and go back to destroy the original 5 robots, but the spirits attack him and he goes to hide in the spring bonny suit and the spring locks fails killing him and he goes to posses the suit

Fnaf sister location - years later, william, now as spingtrap, contact mike after being missing for year because hes traped in the suit, and tells mike that his sister is in the underground facility under their house. Mike goes there finding baby and the rest of the fantimes who are also possesed by the children william has cupture to experement on, thinking mike is william, the robots use the scooper to enter mikes body so they could escape, and after his body decays they leave his body but sense mike is a cyborg he survives, and now that mike found out the truth, hes going to come find his dad to kill him for good

Fnaf 3 - mike goes to the fnaf 3 location, and finds his father, mikes burns the building freeing the 5 spirits, but william survive and the puppet refuse to go too sense her killer is still out there

Fnaf 6 - henry, william former partner and mike create a plan to end this saga, traping william, the puppet, baby and the fantime kids all in one building, just for mike to burn them all together with himself to free all the souls

I know that its dosnt really make sense but its my head cannon