I've been playing this hack on and off today with type randomization and palette shifting turned on, and I've noticed there seems to be an issue with some 'mons with Ice as (I think) their primary type, where one of their darker colours will be a very vivid and saturated green colour that sticks out from the rest of the Ice palette. Unfortunately I don't have any pictures at the moment, but I'll keep my eye out as I continue playing to see if I can catch it. If it helps I believe one of the 'mons I saw this with was Vileplume. No idea if this hack is being worked on at all anymore since your last reply was almost a year ago now, but I figured I might as well bring it up anyhow just in case.
I'm having a whole lot of fun with it by the way, it's interesting how cute some Pokémon can look with a simple palette swap. I've got an Ice/Grass Alolan Raichu I named "Sour" that looks super cute!