It's based on CS4231 so yes, it'll work in DOS and Windows 9x.

....after a TSR is loaded. Many WSS cards carried this chip and needed a TSR loaded to initialize a sound blaster mode.

at least there's a ymf262-m on it

what is TSR and how easy or hard is it to load

It's a little pricey for what it seems to offer. I can't tell for sure if there is a wavetable ROM on the board or not, but it looks like it might.

An SB Pro-compatible card with OPL3, decent onboard wavetable, and wavetable header should be between $15-$20.

A TSR (Terminate and Stay Resident) is a program that you load in DOS (usually in autoexec.bat, so during startup) which loads itself into memory and then terminates. It stays in the memory until you remove it or restart the computer.