The above photo shows gold hardware finishes as you had mentioned wanting to incorporate. I think this could be a fun option and will give the space an interesting and eclectic feel. Mixing metals is completely okay as long as it's not over done. Stick to two finishes only- in this case, ​chrome and gold/bronze/brass. I would also suggest using different finishes on the different metals, so if your chrome is polished, do a matte or brushed gold. Use the gold accent metal in several places so it looks intentional. (Cabinet pulls, mirror, sconces, chandelier). You could even add some more gold accessories on walls or surfaces.

As we just discussed, a large mirror with two sconces will create balance and allow space for all of the pieces. A larger mirror will also help to reflect more natural light. The clean lines of both the sconces and the mirror won't compete with the natural textures of the marble and wood (and also lets your chandelier stand out if you decide to do it!)
•Hang the mirror in the center of the vanity, and a couple of inches above the backsplash.
•Hang the sconces so their center point is close to your eye level, and center them between the edge of the mirror and the edge of the vanity.
•I think the chandelier is a fun idea and I'd say go for it. Having glass between the shower and tub keeps the space open so you'll be able to see the chandelier through the shower glass.

If you decide on gold metals, I would stick with a warm white paint color. A white with yellow undertones will compliment the gold and will also mimic the affect of natural sunlight. (see paint options below).

I have also included a version using all chrome metals with some cool gray paint options below.

I would suggest getting sample jars of a couple whites or a couple blues depending on what color scheme you choose. The lighting and materials in the room play a huge part in what the color will actually look like.

It has been a pleasure working with you again, please let me know if you have any questions!