To my knowledge the Obligator doesn't do anything to stop card effects, it just enforces verbal deals that go past the current interval.
Unless it explicitly says otherwise, yes.
I don't believe there's anything in the rules that would forbid this, so sure go nuts.
Correct, you can only do the 2->1 conversion with your own resources.
So if a problem requires exactly 1 skaa, and you and another player have exactly 1 of some other resource each then there's no way for you to combine your 2 into a skaa.
I've always assumed the first, but don't know either way.
I believe so.
Probably not, though that's just my gut.
Yes. The Smoker's annoying like that.