Apparently Granolah is a bit stronger than Gas (Unused) and has a relatively comfortable advantage over MI Vegeta. Gas should win with great difficulty.
Hard to say as we have yet to really see how well Gas fights and adapts to his powers. I'll say Vegeta for now, as at least Granolah had the motivation of revenge on his mind against Vegeta. Gas doesn't have that so Vegeta might have an edge in combat intelligence.