would I still need to the Disk 1 music file (at a whopping 160+MB) if I just extracted the difficulty select music and converted it to MP3?

I'd be willing to do that, speed isn't an issue there.

I've got a 1 gig stick and I want to know if there's a way to make it so that once I get to disc 2 in COMI, I don't need to keep the voice AND music files on my stick when I start up ScummVM to load my save in COMI. See, I'd like to keep the sound files uncompressed, because it runs so much faster, ...