I wanted to do this from the beginning; I added Mario & Luigi support to the mod!
basically, their sounds are replaced with their galaxy equivalents, including the cosmic clone's voice.
I finally found the ambient sound I was trying to look for. I had to rip the sound myself (not fun) because nobody else had done it before, so I hope that hour I took trying to find it out of the unnamed files of the game was worth it, because I'm not gonna do that again for a while.