Lay them both landscape.

It can either look really dramatic or too dark, depending on the size of the room as well as your other components. I've attached a couple of images of our work using dark tiles, the smaller bathroom we have surrounded the bath with dark tiles but then balance it with an extra large mirror to bounce the light around the room. The larger bathroom we have taken the floor colour way onto the wall but used a different texture on the walls for drama. Hopefully this gives you more of an idea but you shouldn't to nervous of the room being dark, it's where you can create a contrast as well as textures. Look forward to seeing what you go with in the end.

It's the floor colour that's the main problem, neither one thing nor the other, and certainly wrong with the benchtop. Leave the wall tiles if you like that sort of thing and find a way of covering the floor probably with laminate planks on an underlay. We have a European Birch golden coloured timber floor but softer grey splashback and it looks fine. It's not an award winner but the floor and cabinet carcases had been there twenty years and it was affordable. Don't even think about painting the floor or putting down mats but a clear plastic runner in front of the sink works well for us.

You can select a mosaic tile that is already laid in herringbone fashion - usually available in smaller tiles of better quality material like marble, or you can select individual rectangular tiles - depending on the proportions of the tile (ie 100 x 200 or longer and thinner like 50 x 400mm), this will give you an entirely different look that you need to be able to visualise to make a final decision.