If you're going full philosophy of science, are these alternative theories falsifiable in the first place? Much of this kind of argument turns into philosophy and metaphysics instead of empirical science.
Imagine what would happen if we transplanted a head, or full brain, and the consciousness self would still remain the same, like with other organ transplantation.
We'll see!
I am saying: we can guess, but we don't know. I am not saying it's likely. I just want to remain precise in what are theories. It is a theory that consciousness "lives" inside the physical brain, as much as it is one that it doesn't. It is physically possible that it exists energetically and moves and stays with "the larger chunk of body".