Well, in The Fourth Closet, it is revealed that not only is Charlie a robot, but also that Ella, the old doll she used to have, was built inside of her. Henry poured all of his grief into that doll, and that is what gave the robotic Charlie life.

Well, when I think about that. It makes me wonder if just as Charlie had the Ella doll built within her, what if Gregory (the robotic recreation of the Crying Child) had the Fredbear Plush built within him. What if deep inside Gregory's inner workings, his good ol' friend Fredbear could be found.

I mean, it would only make sense. Just as Henry poured all of his emotions into the doll Ella, the Crying Child poured all of his emotions into the Fredbear Plush.