Alright, so this what I figured out with the Atari emulator:

B = Fire
Select = Game Select Switch
Start = Game Start
L = Hard Difficulty
L2= Easy Difficulty

The last one was tricky, as you would think R would have changed difficulty instead of L2. I bound L2 to my R button to test with and I was happy to see it work, but dumbfounded by the control scheme. So the other 3 face buttons and R doesn’t do anything from what I can tell.

I just need to know how the heck to enable the 2nd controller and I will be OK, I can live without 2 player DK on the SNES for now.