I'd put Johnson above Obama.
I'd put Paul above him as well.
No. Paul has your typical anti-gay evangelical troll views. He doesn't support civil unions, doesn't support anti-discrimination laws, doesn't support anti-bullying measures, etc. At least in public view (and probably privately as well, where both are more gay-friendly), Huntsman is not that different from Obama, though.
No idea what Johnson's positions are; he's just a joke.
I haven't heard of a joke 2-term governor with a billion dollar surplus and highest job creation for his state out of all states and is still very popular where people know him.
Paul and Johnson would be slap bang in the middle of the pro/anti gay scale because both of them seem to want to just stay out of it. Why should the government care if you are gay? My favourite thing about Paul is that though his personal views don't support gay marriage, he doesn't let that get in the way of his view that the government shouldn't care if you're gay.