Responses
No biggie. When I was reading one of the chapters ( I don't remember which one was it) for some time Jamie behaved weird as in being like another person and that's when Aimee saw him and ask him why did he possessed that boy or something along those lines. That's probably why Aimee said that Jamie is easily possessed. And about the doll if Ethan wasn't "exorcised" from Jamie's body, maybe he's the one possessing the doll. That's only my guess.
I know who the heck Ethan is!!!
If I'm not mistaken, and correct me if I'm wrong, but I think he is Jamie's stepmom's son. remember what he told Jamie when he ask him about his mom? that she didn't look him at all, even when they were together, and after Ethan died his mom remarried and took care of her stepchildren.
I think that's why Ethan tried to kill Jamie's sister and isolate him. He's resentful of her because he thinks that she didn't love him but she loves her stepchildren.