First, I love clawfoot tubs -- sorry to see that go, but you will enjoy your new shower.

I am attaching inspo pics of showers with 24x48 wall tiles similar to your three tiles with marble veining. The first photo is from Houzz, the next two were taken at an open house for a new construction build in my area. Both used a neutral color on the floor, with minimal movement.

I would use the square mosaic tile on the shower pan, not the penny-round (it adds a lot of extra grout). That wallpaper is too busy -- I don't think it adds anything. Maybe do a full backsplash of the wall tile. (I'm not a Pro, hopefully, they will chime in.)

Contemporary Master Bathroom · More Info

Thanks, I'm not getting rid of the tub; just adding a shower in the area where you see the tile samples setting.

Oh, now I see -- the tub is staying and there is a separate space for the shower. Is the bathroom T-shaped? Shower to the right and WC to the left?

I do not see an obvious place for the wallpaper to stop, unless it extends across the wall -- there's no clear demarcation on the wall between the sink area and the makeup area. Maybe add a wall-mounted makeup mirror to give more counter space? Otherwise, I think the vanity/dressing area looks good the way it is.

So happy that the claw foot tub is staying!

I like the large tile in the back out of the ones in your photo. The tile could work with different accent colors = you will be able to change the look of the room without needing to gut your shower.

Personally, I don't like faux marble tiles/slabs - 99% of the ones I've seen look very fake = I'd rather use genuine marble tiles or select a tile that isn't trying to imitate marble. Also, faux marble tiles have become an overly mass-produced and predictable "safe" choice for the past several years. Faux marble has become the default tile (and countertop material) selected by tract home builders.

The only faux marble tile bathroom that I've really liked is @chispa 's bathroom (I think it's one of her guest bathrooms):

She provided a link for the tiles she used:

https://www.atlasconcorde.com/en

If you use faux marble tiles, you need to have a good installer - when the tile installer doesn't pre-plan how to lay the tiles out in order to have the veining run from one tile to the other ones around it, it just looks messy (I've also seen where someone installed two of the same tiles near each other (had the exact veining pattern).

Look at how the veining on the tiles on chispa's bathroom floor flow from one tile to the next one. The result is that it looks like a slab of marble was cut into tiles and installed on the floor (I know that she used the tile in a shower also - I assume it's in this same guest bathroom),

I like the large tile but it's so creamy next to the vanity top (white quartz with blue and gray veining). I don't really like the quartz because it's so hard to work with but can't afford to change it. I was thinking about using the solid white square piece in a 24x48 on the shower wall and the hex on the shower floor.

It is T shaped with water closet to left of tub and shower to the right.