This is a cool character! One thing to consider is your saturation levels, it appears that you use the same saturation recipe on most of the variants. Sautration will bring a lot of attention to specific areas of a character, so consider using it to draw focus.
For example if you take a look at the first character, there are some really extremely saturated blues and greens, I would personally pick one of those to be the leading color or main character, if you have two colors that are that are competing for the main spot in saturation they start to fight eachother instead of work together.
Another thing to consider is strategically placing the saturation, so for example on character 1 you have extreme saturation in various areas all around the charracter, so my eyes get drawn to the heel of the shoe, then the apron, then sword, shield, armpad, color and then the face. I would consider adjusting the saturation levels away from so many areas and focus them on where you want to draw the viewers attention, typically the face. Hopefully that makes some sense.
