No.

Bud, what about the head? Should it be fully trible or it can be mixed style?

If it looks good you have free hands. The only wish I guess, is for the face to not be overly expressive.

An example would be the head I made when I first started Toribash, here.

One more question what do you mean by primary void color? Should it be a background color of all set with a white/orange lines or should it be as a black lines mostly on white bg?

Good question, I may have been a bit unclear in the first post, lol
I want Void to be used excessively. Pure wasn't originally part of the idea at all, but I allowed it and people seem to have taken it as a requirement, and way overused it.
The whole set should in general be Void with Orange details. If I zoom in and see you've made use of some pure or whatever color for shading, or anything really, then that's just fine with me. As long as the Void is the primary color :)

If you arе ok with my presence then I'm in

Sounds good to me. Just remember to post wips.

I'll give this a shot since its my main art style, just hope my internet does not start being a bitch and ill start throwing some wips via whisper if you dont mind

Awesome, I love the head! Could you maybe add a tiny hint at something twisted behind the orange, in the front of the head? Like, some abstract simple implication of a face in the normal place it should be?
Great work!