YUME NIKKI?? In MY SM64COOP??? I've never hit the download button so fast in my life!
The models look adorable, and the voice choices felt right despite being only sound effects from Yume Nikki, given they have pretty much no voice clips there (unless you count the 3D Yume Nikki -Dream Diary- game on Steam and even then it's a stretch because they rarely speak there if at all.)
My one suggestion is making them recolorable and maybe include at least Monoe and Poniko in the future, but that's not a deal-breaker in the slightest. You have no freaking idea how happy this mod made me already!
UPDATE: After playing this mod for quite a while, I've come to want to suggest one more thing, which, at the end of the day might be just a me thing:
The idea of adding the ending's song as the voice for dying animations was very clever, but it also being the sound for falling makes it get real old real fast, in my honest opinion (even though you can die by falling off stages too, I know.)
I'd suggest changing the falling voice to the scream used when getting burned, or even the slowed down version of that scream that's used by NPCs in the original game instead, and leave the ending song just for the deaths by 0 health.