Hope you have more flooring stashed away since you will need it. As for tile layout the best is to draw the shower wall you will see first , draw to scale and draw the tiles to scale and see which layout you like better, keep in mind that size tile needs to be either 1/3 offset or just stacked. I would say it also depends on the tile since you already have busy stuff going on . Maybe just a simple porcelain in a color from the floor . You need a new window made for showers too.I would tell you to test pebble flooring for the shower I do not like it on bare feet and it will also add another pattern to the bathroom so I would just do smaller tile in the same tile as the walls also no accent tile

Also....a bit of wall space for your towels would help keep the bathroom looking neat and tidy.

How much of that back wall is going to be your shower? I agree with Patricia that your shower has to have simple tile. One color from the floor (the caramel or creamy white) would work best. Heed her warning about the pebble tile floor if you’ve never had one. So far, your bathroom looks very nice!

Patricia's suggestion is excellent! A to-scale drawing is about the best way to visualize unless you have a program that will simulate different types of tiles and orientations.

Total rip out of garden tub and entire back wall will be tile Shower. Should tile also be vertical as flooring? he will tile around window. Water will not hit tile so it is okay and smoked (?) glass. Thinking big maybe linen Or cotton look tile. So no listello?