Would it make sense if the Player was..... Elliot?
By the Lore we have now... would that make sense? What if we after Elliot's death, Playtime started working on the prototype project, a robot-like human being that would mimick a real human appearance (that's why he can recreate voices) and so the endoskeleton (1006) was made. He would come out as a test to see if the cientists could take the risk of transferring elliot's body and soul into a robot, and maybe even more people could come back to life (Stella Greybur would be one probably lol) and so they finally turn Elliot into this robot (that would explain why that fall in the end of chapter 3 didn't killed us) but upgrading everything that was missing on 1006, such as the human skin (that's why he Prototype never got out) and send the letter to us so Harley could study our body and recreate our skin so the Prototype and Sawyer would escape (That could be why Doctor wants to "test us" trough chapter 4) Also the reason why Prototype is much bigger and have a more monster-like appearance is because him, woking with the Doctor, upgraded his body in order to survive and kill others (Considering that the toys are not united anymore and he wouldn't be strong enought to fight off agaisnt rebel bigger bodies) that's also maybe why he collected other toy parts? Maybe after the jumpscares they would take us to the Lab so 1006 and Harley can study us (woking together to escape) and the reason the children are alive and sleeping is because he's keeping their bodies fresh and healthy to make sure he has skin to use, considering he couldn't feed them forever I mean that makes some kind of sense right?