Hmmm, I don't think splitting "person" into mind and body to go on and claim the mind always necessarily owns the body solves the problem. I agree that way you clear my first objection: It's no longer a circle. "You"/"Person" is in the mind owning the body. No circle.

But you now run into the second difficulty with speed. Let's see if you agree to this: 

1.) If the body  were "normal" property, you'd be able to give it away or sell it like all other property. 

2.) So if we want to call it property, there must be some reason to disallow selling it.

3.) Your argument against selling it is that the locus of the mind is in the body. The mind can't leave the body, hence it can't transfer ownership of the body.

4.) Your protection against slavery is as strong as your argument in point 3.

Do you agree to these points? If not, which point not?