Would it be possible to export the cloathings, hair styles, items, weapons and other stuff as single layers? This would allow to create near endless variations of characters.
That is possible. I was considering releasing the PSD layered file as a separate purchase once I accumulated enough layers. The same goes for the Busts but it's a bit more tricky. Would require users to be familiar with photoshop/gimp editing and layers. So debating if that's something I should list or not.
One of my favorites artists whos Patreon I am releases a spritesheet for every component (base/body, tops, bottoms, facial hair, hair, items/weapons) with all the animation frames. You just have to place them on top in the correct order. It's really simply an grants a lot of freedom.
Btw: Do you have a Patreon including your work?
If you are interested in pursuing the layers idea - I'm a web dev and would be happy to build a character generator using your graphics that you can then release.