Whomever hung the light above the tub should lose his electrical license this very minute . If that is you , it is out of electrical CODE. What is the waterproofing plan for the shower?

And the answer to your tile question is marble is best with a plain white or plain pale gray, or MORE OF ITSELF. No rock anything please. Take the light down over the tub. .......

"The National Electric Code (NEC) from 2011 requires that any part of a light fixture, including crystals dangling from chandeliers, must be a minimum of 8 feet above the highest portion of a tub's walls. This no-chandelier zone extends out horizontally 3 feet around the tub rim."

I would start by asking what style is your home? I like the cool clean colors so far, but it's difficult to know which direction to lead you without seeing your style.