1. Depends. Doesn't change the constraint.<quoted text>
Would that be a latent or manifest constraint? And why do you believe marriage isn't above love?
The Fundamental Goal of Evolution. hmmmm... missed that one at university. Also, doesn't seem to come up on a web search! BUT... if it did, I am pretty certain the goal of evolution would be a lot closer to supporting variety, differences and changes in living species over time than some silly non-evolutionary concern like, say, denying gay people marriage.
2. Where did I say that?
4. Gay couples are an evolutionary blunder.