Doom SNES Rom Hacking - Custom Sound Effects
I found a way to modify the sound effects using a DOS Program called Snessor. I had access to most of the sound files (I also found 2 unused ones) and replaced a few with some meme junk. The interesting thing is that the Sounds all have a certain length to them so if you would replace one it still has the length of the original sound which means it would cut off if the sound is longer...
Snessor does compress the sound files so you can hear them in game.