I think you'll have to clarify re: the inescapable point - it's confusing to me!
Re: social contract theory, tbh it doesn't really engage with meta-ethical issues, more that it creates a model that tries to justify why we ever afford people "rights" in any sense (although the "rights" it deals with are basically just social constructs).
I'll answer this first, mostly because I don't know what to think about the other questions yet

Well, what I mean is, some theories could be perceived to just be asserting different interpretations of objective moral fact(s).
I'll just show with an example (I apologise to anyone trying to follow this that hasn't looked into or studied moral Phil before, but here's something that will help you -
http://plato.stanford.edu/ - use the search bar).
*I'm not saying this is what X group holding X moral philosophy would say, I'm just showing something that sort of puzzles me
Consequentialism - "There is one objective moral fact; only consequences matter", and if we want to branch:
Preference utilitarian - "There is one objective moral fact; we should do what leads to the max utility and the least suffering, where utility is fulfilled weight preferences and suffering is frustrated preferences"
Or,
Relativism - "There is one objective moral fact; morality depends on societal standards"
Nihilism - "There is one objective moral fact; nothing is inherently right or wrong"
I'm not really making an argument here - I'm confident I'm missing something - I'm just throwing it out there.
But can't rights explain the nature of moral judgment? (Or, couldn't you try to use rights as an explanation?, re SCT and meta-ethics?)
So, are you guys saying that if God is the basis of moral facts, then objective morality doesn't exist because moral facts are just dependent on God's personal opinion? That's actually pretty cool.