WSS is technically the best DOS sound standard - but I'm not aware of any game that actually uses its 48kHz vs SB16 44kHz (hell, there are precious few that actually do 16b 44kHz and not just 8b 22kHz).
Fundamental question is: are we looking at best compatibility for Soundblaster (Pro/16)-supporting titles, or best compatibility for highest number of standards?
In terms of a single card, I'd say go for the best ALS100 card you can find:
- OPL3 (or 100% clone)
- SBPro2 and full SB16 (including high DMA)
- bug-free MPU401
- no TSRs
Its SB compatibility is good, but not perfect.
Multi-card setup:
- Original Sound Blaster, or replica, preferably with CMS chips, for SB and AdLib (and Game Blaster if you add CMS)
- MPU401 or clone (MagicQuest, HardMPU etc) for intelligent mode MIDI (and bug-free MPU401), connected to at least an SC-55 or SCB-55
- AWE64 or perhaps better CT3670 (same DSP, but with SIMM slot for RAM) for SB16 and AWE
- PnP SBPro2-clone with WSS (why PnP? So you can choose to init either it or the AWE, so you don't need to use really obscure resource settings to run both, and can choose not to enable OPL)
- for good measure you can add Covox, Tandy and SSI-2001 replicas as well
- it should be possible to add a GUS without major resource issues too, if you do find one for an accepable price.
Of course, doing all this in one system does need a LOT of ISA slots, I'm counting seven. And games that like the oldest hardware probably want a CPU that is slower than makes sense with AWE and GUS. But it's all within the realm of possibility, if not optimal for everything at once.