[HOURAISAN]

Ah, okay, that distinction between transcription and kunyomi cleared that up. As for ももずみ - I pulled that out of my ass, because I couldn't think of anything else, and I wanted to make a point out how seemingly out-of-nowhere くだら shows up (note the "I think" in the original post)

And yes, I am very aware that Classical Korean is going to have issues when transcribed using Yamato Japanese, just like how Yayoi Japanese is going to have issues when transcribed using Late Old Chinese. I didn't want to assume that くだら wasn't of native Japanese origin, but I really should have just asked for the etymology of the pronunciations instead >.>

Anyways, thanks.