A soft, warm grey shade would look lovely, and can be as dark or light as you want. A warmer shade will work with the brown stained wood floor, and the grey will complement the black granite. You could have an undertone of green, blue or tan if you didn't want a pure grey. And it would look nice with any silver metal hardware, either polished or satin/brushed, so you could choose pewter, chrome or nickel. It would still work with white trim too.

It depends on the overall theme of your house and if there are any special requirements for either marble or wood. Wood is softer to tread on than Marble and Marble is easier to clean.

I really liked the indirect lighting and the bar light fixture.

The spaces look beautiful and warm. My suggestion wood be, to retain the warmth . Add some wooded flooring here and there along with some rugs. Since the whole colour pallette is creams and browns. Use a warmer shade for the rugs like a darker brown or beige or add white rugs just to break the beige monotony. Some accent furniture in black or dark brown leather would add some aesthetic as well. You can try popping in some plain red chairs as well. Try to avoid patterns in the furniture and rugs so that they don't clash with the flooring.