Here is the tile and my ugly powder room now

IMO the penny tiles are a PITA to keep clean and unless you go dark grout they look awful in no time So do the penny tile go black grout and do the black counter I have black granite in my master bathroom and I do not find it one bit harder to clean that the white one in my main bathrooom . Do not do the backsplash piece on the side with the new top

Those are hex tiles. Penny tiles are round and take a lot more grout. Grout them in a mid-grey and they will be fine (I grew up with 1" white hex tiles from 1918. They are not hard to keep clean.)

As far as the granite is concerned, take your tiles to the stone and see what looks best. I think it will probably be the dark grey.

Thank you both for your feedback. I really appreciate it.

Really like your tile choice!

KR! What a gorgeous powder room!

KR. Where did you get your fabulous mirror?

Thank you. I got it from Z Gallerie, but Wayfair has a lot of similar mirrors as well.

This is how our powder room turned out. We used a little different floor. We love it!