It seems like ideally the party wall between an unconditioned garage and living space is:

1) air sealed (performance and health/safety)–but do you also put an air barrier on the “outside”/garage side in addition to say, taped plywood sheathing or intello on the interior?

2) insulated–but how much compared to an ordinary exterior wall (e.g. if the other exterior walls are R35, what to aim for this party wall?)

3) easy to drywall on the “outside”/garage side for fire resistance/code

I can’t imagine that people are just hanging drywall on top of what would normally be rainscreen battens (seems like it’d be really difficult to get a flat wall). But it also seems like it’d be difficult to get to a higher insulation value without something beyond a cavity-filled 2×6 wall.

Are people building double stud walls in this case? If they are, do the same theoretical moisture issues of double stud walls apply in this context?