First, WELCOME!
Second, love your sink and the look your are going for. I don't know about the polished verses matt finished tiles. If you use small tiles for the floor matt or polished will work without issue because the grout lines will provide traction. If you use large tiles on the floor it is often recommended that you look at the slip factor when the tile is wet. Floor tiles need to be stronger than wall tiles to withstand the abrasion and the forces they are exposed to.

Here is a Houzz article that might be helpful in explaining the aspects of tile ratings:

https://www.houzz.com/magazine/your-floor-how-to-shop-for-tile-stsetivw-vs~508253-Floor--How-to-Shop-for-Tile

I linked the "finished bathroom thread" that Hobokenkitchen started a while back. I want you to see @ mabeldingeldine's bathroom near the end. It is so cute and charming.

Here is a link that might be useful: Finished bathroom thread that Hobokenkitchen started.

A lot of times "gloss" can be in the eye of the beholder. The catch with porcelain gloss hex tiles is that they'll usually never be as shiny as a polished stone; polished marble hex for example.

Same with "white". One person's white can be another person's "ivory" or "cream".

So definitely see any tile in person if you can before you purchase.

Not sure where you are located, but HD does carry an advertised gloss white hex. That might be an easy starting point for comparison.

Grout colors can be tough. The thing is that a bright white grout can sometimes look too stark and startling. Usually a light gray or a silver will look better, even when white is what was desired. But again, it's your floor, and your eye knows what you want best, so you can make small sample boards to help guide you through that if you're so inclined.

I don't mean to be too forward, but over that plank subfloor you'll probably want a layer of plywood then some sort of transition material; cement board or a tile membrane. A membrane can help so much in older houses.

If your house is a bit wonky and you need to minimize the floor thickness, use 1/2" plywood over the planking for added floor stiffness. Then considering Ditra (1/8" thick) as an uncoupling membrane over the plywood. Actually, nix the Ditra. You're using a mosaic tile, so consider something along the lines to Durock Tile Membrane or Nobel CIS.

Hi Rhea. Absolutely LOVE your vanity and mirror! You're off to a great start. While I love the look of the small hex tiles, my only hesitation would be the upkeep.

Your situation may be entirely different than mine, but I found when we had white tile on our bathroom floor it showed every. single. strand of hair, speck of dust, etc. etc. and I was NOT about keeping it mopped daily. So...you get the (not-so-pretty) picture. Of course that was our main bath so it got some heavy use by 3 large men ;)

If your room isn't used heavily and/or if you're fine with the upkeep, I say go for it!! It's beautiful!