Blackthorne is all pre-rendered, it's just not very optimized. Not a lot of people knew how to properly program for the 32X, I don't think.
For Space Harrier, I think the Genesis does the percussion and bass and the 32X does everything else. Or maybe the Genesis does everything BUT the percussion and the bass, can't remember. In After Burner the 32X does all of the sound. I have a recording somewhere of JUST the 32X audio on some games. The Genesis' sound chip is used almost exclusively in most 32X games. Cosmic Carnage, for example, is 100% Genesis sound and music. Same with Shadow Squadron. Knuckles' Chaotix uses the 32X only for the drums. The 32X is simply programmed to sound like the arcade game they're running. No emulation. Probably not powerful enough. But you can make it sound however you want. It can even play .MOD files and I think .XM files. But not MP3, no way.