Ex Post Facto refers to criminal law, not simple legal definitions or standards. The Ex Post Facto ruling on Canal Zone citizenship is what gave McCain ‘natural born citizenship’ status re 8 U.S.C. §1403 which retroactively recognized canal zone citizenship. (the bill, passed in 1952 was made retroactive to Feb, 1904)
Have you even looked at one of the many images, of John McCain's birth certificate, floating around the web? It clearly states, on every single version I've ever seen, that he was born in Colon, Panama, which has never been in the Canal Zone.
Even if he had been born in the Canal Zone, there is no law that can be passed that supercedes the Constitution on the matter.
You would have us believe that John McCain suddenly became a natural born citizen at age 16. But, he either was at birth, or he was not, and is not. The Constitution forbids changing that after the fact.
McCain doesn’t qualify according to the standards either. Sorry.