You can easily change the skin color for any of the G2 characters that are RS compatible and also various body part sets that you can use to customize the face, eyes, hair, etc.
The G3 characters can also be recolored in an photo type editor (photoshop, affinity, etc.) that support psd files.
See my CTA Tutorials on the YouTube channel CTAStepByStep
Check out EZColors for CTA. The easy way to change Render Styled (RS) colors.