Even if he did he could do some real damage before then. Not just in foreign policy. Hillary wouldn't put a pro-life anti-LGBT appointment to the Supreme Court. Trump would. That would have consequences long past his presidency.
I'm not to sure of this. First, Trump doesn't speak negatively of gays and most of the neocons (most of the old guard, like the Bush family) reject anti-gay (anti-anybody really) legislation. This is the Democratic-hype machine creeping into your head. Really, the only anti-gay is the Christian Fundies and Trump has made an enemy of those people because he doesn't support their notions. Half the Christian right is going with him because they just think the other issues are more important, and the other half is in conflict. The Christian Right has been constantly declining in the party as they have been incorporating more liberals and libertarians. It's just not like it was even ten years ago -- the religious vote is not shaping the party as much. At least, no more than the Democratic.