Wall paper in a texture like grasscloth. Dark.

Grass cloth looks absolutely stunning cut into even squares and hung running in different directions. All of the corners get silver clavos. You need a skilled paperhanger good with math skills for this application. Will try and post a picture of this application from my showroom. We use it alot in dining rooms and bathrooms.

I would have never thought of grass cloth or wall paper in a bathroom due to moisture.

I would leave the shower area all Carrera marble so you are not breaking up that space and it will be more elegant and streamlined.The mosaic is perfect as the backsplash and maybe the shower floor? Or, you could consider using it to accent the entire vanity wall to the ceiling as a feature wall. I assume you will have a mirror or medicine cabinet above the vanity so you wont have to pay for an entire wall of mosaic. If you still want the mosaic in the shower area just put a thin horizontal stripe of it but not in the shampoo recesses. I love your idea for the Carrera vanity top. That will be gorgeous! Wall color in a bluish grey in the light or midtoned range would be perfect.

P.s. If you use the mosaic as the shower floor I would not do the feature wall, just a backsplash.

You can have a square of mosiac in the center of the wall or if you do it on the floor a small line in mid wall.- see a few similar ideas we did.

As an architect my approach to interior design is less is more. What i understand is you have two contrasting colors and an effctive element, the tiles. First thing you should do is covering the whole space in a harmony with the two colors. İ personally think that two contrasting colors are enough to create the expected visual effects,but if you want to use tiles stricktly, use them to create a focus point. Consider that the material would directly catches to eyes when you step in. Thats why dont use them near the closet whichi would not like to see in first step.

Pratt & Lambert Winter's Gate would be subtle...BM Marilyn's Dress would be more dramatic. I agree with Klein that you need more use of the mosaic to tie together. Otherwise, it will look like an afterthought.

I agree mosaic is a trend but I do like this combo...I too think placing them on shower floor would be a nice "pop" to change it up a bit AND easier removal down the road should you tire of them; save a few pieces of other tiles to use for replacement.

We did the same exact palette.