Looks fine not covering the whole wall. Now that it’s done I’d probably leave it. You can do a mirror with a rim. But show us a sample before committing. Pretty space

Personally I would have covered the whole wall. However, this still looks really nice and I do love the tile. I would do a frameless mirror, a lighter frame would not work. On either side of the tile, could you have slim wall sconces added?? Finally I love the handles, it is a great monochromatic look. Lighter handles would again just stick out too much. Can’t wait to see the finished project.