As a decorator, i have never advised on colour schemes - one man's meat, etc. You are the one who will have to live with the end result.
One piece of advice i will give you: whatever colour you choose to compliment the charcoal, do NOT test it on a bare wall - most folk who do, use a brush and put much more paint on the surface than would be the norm with a roller. And, when it comes time to be painted over, you will usually find it bleeds through.
Buy a cheap roll of lining paper and cut a sizeable piece which should then be painted and attached (blue-tack, cellotape, whatevs) to the wall adjacent to the charcoal to judge whether it is suitable.