The face and skin textures are really good. They look like different persons, some look older and the black-haired one on the bottom left even looks angry or unhappy.
I like the cat-girl option! It’s always good to be have more options to extend the character to another race. The cat-girl does look human enough so that she might just be going to a costume-party:) Which reminds me.. I don’t know if anybody suggested this but a couple of masks could be useful for human characters. Maybe Guy Fawkes mask, a black zorro mask and some “Eyes Wide Shut”-masks? There are some metal-masks in the existing humans but they are not very mask-like since they cover the whole face and are not very easily recognisable as masks.