You're the one who was so concrete about the separation of the three primary components in the first place:
So really, what you're saying now is basically what I've been arguing the whole time. The main difference is that you're depending on Terra transferring not only his mind, but his soul, to the LS. We have not heard anything of the LS containing a soul, nor of Xehanort transferring his soul into Terra alongside his heart. We have no good reason to suspect he would have even wanted to carry his soul over, since the soul is only an energy source for the body, as far as we know.
While I can now acknowledge the possibility of your theory, I still can't give it much credence, because it provides little reason to doubt the default hypothesis.
It's called speculation, and you're being very disrespectful regarding the way he thinks and presents his ideas. He's given sound facts(Xehanort Report) that backs up his theory. No the "mind" concept hasn't been introduced, but it doesn't stop speculation. I've heard a lot more off the wall theories.