So the short version...
The current linux firmware package doesn't work with the Wifi on the MS Surface GO, and the instructions to copy the downloaded board.bin and copy over firmware-4.bin were incorrect. It actually saw the Wifi adapter after I did that and it tried scanning for wireless networks but never got any further.
Since the Killerwifi board.bin and the linux firmware board.bin were the exact same size (whereas the firmware files were orders of magnitude larger), I tried replacing board.bin instead and can report after rebooting that the Wifi now works.