Then I remembered that I set the default options in ScummVM to use "True Roland MT-32 (Disable GM Emulation)". In KQ6, it had the "Use Default Options" checked under the MT-32 Tab. All I had to do was un-check it. Ack!!! Thanks for posting the solution! I was like "why is a...

Oh, good God, I hope they get it running in Crossover.

I actually found the ScummVM boards only just now, by googling "quest for glory ii crossover," so there you go.