I've realised something about Sister Location and FNAF4.
They're connected in more ways then one.
Sure, you know about the breaker room. But there's more.
Funtime Freddy and Baby can pull children into their stomach. Like eating them. How do you eat? With your mouth.
Nightmare Fredbear and Nightmare have mouths on their stomachs.
As for the Fake Ending, it actually takes place inside the house. William Afton is watching TV. Looking at the breaker room, the Living Room is where one of the secret entrances is. Ennard could have snuck in and attacked Afton.
But then there's Baby. Who killed Afton's daughter.
In the end, they weren't evil. They wanted the family back together, or, at least, what's left of it.