I really dislike the possession theory. I think on top of being a bit creepy, it kinda diminishes their connection to Wanda. Because then they're not her reincarnated children anymore, but just two random kids who end up possessed by them. I think there is something more poetic about Billy and Tommy being destined to be reborn as opposed to just breaking in the body of the first two kids they see. Not to mention that it raises a lot of questions about consent, like... did their consciousness get rewritten after they got ''possessed''? Are they even the same people as they were before? Are the Minimoffs controlling them like puppets? I think it becomes even more problematic when you think about the fact that Billy and Tommy Maximoff's origins in the MCU were directly related to the Hex, which also took people's free will. I would prefer if they didn't go there.