Hi there, I've just moved this to Design Dilemmas for you!

Definitely go dark - maybe even another accent color, just for a cool contrasting look.

There is a lot going on there. Do you want help other than with a color? I agree with going with a dark color. I think it will tie the wall under and the ceiling over together. Even though in most cases I do not recommend having an accent wall. I think this is one of those exceptions.

yes match it to the wall.

I usually would say no to painting the ceiling the same colour as the wall, but in this case it is such a small section and does not run off into other ceiling spaces. So, yes, I would paint it the same colour as your accent wall.

I do not like accent walls either but in this case it is a stand alone wall and I think it will look dramatic and be a nice back drop for your furnishings and art. ( Love the dog paintings). And yes carry it up on the ceiling.