The Supreme Court will rule one way or the other. I predict they will rule that his is natural born, but irrespective, it’s an argument for the Supreme Court to decide, and it really doesn’t matter what any of us think.
You are correct. The Supreme Court has already established that to be classified as a "natural born citizen", both of your parents must be citizens at the time of your birth (Minor vs. Happersett). Rubio does not meet this standard and cannot be eligible to serve as Vice President or President. The preservation of our Constitution is far more valuable to any one of us than any candidate we might wish to have elected.
I wonder on the issue of defining NBC if the SCOTUSA has any more authority or standing than defining if ‘a rose is a rose’. SCOTUSA might give a decision on eligibility but it seems to me there could be a POTUSA ignoring such as well as a Congressional action nullifying such a decision. A real question on all of the present day quandary is why such exists today.