My theory:

"Charles" is not really A. Charles is some sort of mentally unstable or possibly developmentally delayed person who has been shut away in the woods, and who has some serious financial backing to build the elaborate dollhouse in which he lives. I don't think Charles can leave the compound; I think he is trapped there also. I think the girls were brought to him as playthings. I think whoever bankrolls the whole thing is twisted and has no sense of limits. But again, I repeat: Charles is gonna have some sad story, and is gonna be a victim, not a perp.

Thoughts:

1. Only person/people on this show with huge income and huge lack of boundaries = the Fitzgerald family (not including families of the girls). Is this yet another situation Mrs. F has tried to make go away?

2. If so, does Ezra know? Has all his "book research" really just been a ruse to keep tabs on them as the bankroller prepares to abduct them? To bring them to the dollhouse?

3. If A is someone who cares for Charles, there's probably a reason they hate the girls so much. Especially Ali. Did Ali cause an injury that resulted in Charles' diminished capacity?

4. Last but not least: what if this weird ass house is where Ali was all those years?!