Ok, i've tried the pci_no_detect drivers, with the following results:
In windows:
a) All parts of the drivers are loaded. I originally had a bluescreen error when it tried to load the SB PRO emulation - but I was able to fix this by reserving IRQ 5 in the bios.
b) In windows, DOS programs can seemingly reliably play digital sound. But FM and General Midi do not work at all.
In Pure DOS:
a) The AU30DOS driver reports that it is loaded and SB emulation is enabled.
b) However, none of the emulated SB PRO functions of the sound card work. Attempting digital audio often casues the machine to lock up.
If anyone else has any solutions that might improve things on this generally retro hostile motherboard, I'm prepared to try them.