Is the skin color part of the updated CCmod fork still not working? The description talks about it being a feature, but I don't see any edicts for it in the game.
This might not be the answer you're looking for but while I was messing around in the files I found that if you go into \www\mods and open CC_Gyaru.js in notepad
there's a line like this:
const CCMOD_GYARU_SUFFIX_NONE = '';
If you change it to either of these her skin will be darker when you load in.
const CCMOD_GYARU_SUFFIX_NONE = '_tan';
const CCMOD_GYARU_SUFFIX_NONE = '_tan2';
It's more of a permanent change than an option in game, but if you're just trying to get a good looking Karryn like I am, this works.