Some concept and ideas.
I started with this


problems with them imo was that each one feels more straightforward fanservice than necessary. I made quick 3d blockout to ground my idea a bit and then some over paint on top.

That's more along the lines I am thinking :blush:
I'm playing around with color scheme, hair and details. Which do you like more?

Looking good so far!
I understand what kind of proportions you're looking for but I think the upper body (and possibly head) are way too small compared to the lower body, it feels unbalanced.
Here's a suggestion, what do you think?