Honed and polished is often mixed and is a great look! You might consider using more of that same tile, just in a different shape and pattern, as the accent. Typically marble has a lot pattern all by itself. Adding “accents” to that can quickly overwhelm the eye.

Honed on the floor is a good choice because it won't bounce the light up off the floor. I made a mistake and put polished marble in a bathroom that has a skylight, and the shine is a bit jarring. We're not going to change it though, but now I wish I had picked honed.

IMO an accent tile looks too busy as a backsplach and you run the risk of dating your bathroom quickly depending on the materials you choose. I prefer to use the countertop materials for the splashes (In our master we put in a 6" splash rather than the typical 4" one becauses it provided a better backfrop for the Delta Vero faucets.) Look at pictures of bathrooms that have accent tile for splash vs counter materials to determine which look you like best.