While your concept is fine i do think it may be useful for the ease of artists to possibly have more detail to work from to ensure that you still get what you want even if the only exchange is credit for doing the illustration
you could use picrews to give more detail to the mc like these
or another character creator that has the kind of details you're looking for
and maybe put together or find moodboards that suit the vibe of the setting even if it ends up just being gradients in the final drawing to help set the tone
i personally wouldnt mind pitching in but i'm definitely a "the more details about the character i'm drawing the better" type 