Okay, here is what I have found.

Xwing (floppy version) must work with an MPU IPC-T fine.
It is, however, more sensitive to machine speed than some other games from 1991-1993. I had to disable both internal and external cache in BIOS and fall back to 2x100 Mhz. At this speed, I played cca. 40 minutes, did not come across any MIDI errors.
With cache enabled, MT-32 gen. 1. hangs and freezes with an "Exc. Buffer Overflow" message.

Laser Squad, Spellcasting series worked just fine with cache enabled at 200 Mhz.