The electoral college exists to prevent problems such as the one in question, having a treasonous president, etc.
The college could debate and hammer out the issue of not natural born, and their vote could also be reviewed by the Supreme COurt.
If the electoral college is interpreting constitutional law, then, definitely the Supreme Court would have the power to review that interpretation. I was thinking in terms of challenges to individual electoral votes by parties other than the states. Thanks for the information.