So, looks like I was knocked out for like 12 hours, after being up for 13 dedicated to getting this fixed. >.<
Okay, more fixes. And when its finished, its easy install too. Just replace the p0data61-3.bin files and you're good to go.
No interfering with Hades Workshop, Memoria, or the HD background Mod!
Thing is, I noticed, all the common sfxs were split into 3 or 4 parts, so, all I really had to do was replace all three parts with the original sfx, and voila. The squeak is gone. I could tell this is was right step, when Bio - multiple targets sfxs didn't sound like "wobbly" cartoony noise. (Seen in video part 2 - time: 1:22).
Someone said this, and I agree, reason for the sfxs being split was cause of the speed booster; playing at different frames.
And, instead of using the original, they recorded freshly "new" sfxs for that reason; which is horrible in the end result, clearly.