Suzieque ~ I have a little more time this morning to answer your questions. The tile type is mosaic, it comes in sheets that are connected. The challenge is lining it up just right o that you cannot tell that they came connected in sheets (no 'seams'). Our sheets were mounted on mesh. Another type is connected by rubberish 'dots'. The mesh worked well for us to gently pry out the white tiles we wished to replace with black. However, I believe the tile with the dots is easier to lay properly because there is no chance that excess mesh at the edges will bump into the next sheet as you place them into the thinset. To eliminate this possibility, I spent some time trimming the excess mesh from the edges of my sheets. You can buy hexagon tile already in a couple of patterns from daltile. You can also buy octogan and dot tile fairly easily at most tile stores, where you can have a choice of various dot colors. Its not difficult to create your own pattern, but be ready to be very careful and meticulous in your planning. As I said, I trimmed every mesh sheet, laid them out dry-fit on the bathroom floor, laid the black flowers on top and figured out exactly where they would go marking with a pencil. Then removed each of the white 'flower' tiles and placed the black 'flower' (which I had cut out still connected with mesh holding the 'flower' together) They are not glued, until the whole sheet is placed into the thinset. Since our bathroom was narrow, I was able to make four piles of tile sheets (with the black flowers in place) which were in the order of which they would be laid with the furthest row by the window on top. The jagged edges around the room were covered up by wall base tiles, door trim, or the radiators. By the shower pan litle 1/2 tiles were put in place (these can be bought separately, but a good tile setter can cut these). Lastly, I bought our tile online from American Universal tile. It comes in several sizes and finishes and many colors. We chose 1" matte finish. Send for samples first in the various sizes and finishes. You could also be able to order the daltile or american olean from tile stores. Here is a link that might be useful: Source for our Hexagon Tile

Thank you all SO MUCH for your input! I've decided to go with the blue bathroom... let's just hope mine turns out as lovely as the one in my inspiration photo. I've decided to use Fireclay Tile's Mayan Blue: https://www.fireclaytile.com/tile/colors/detail/mayan-blue/ It is just gorgeous! I'm also going to take lukkiirish's advice to add a few white pencil lines to ease the transition from the tile to the painted wall. Also, like positively_patty mentioned I will be on the lookout for a coordinating rug and/or curtains to pull it all together. It will be a few months until we're finished but I'll be sure to come back to post pictures. I can't thank you all enough for your encouragement!

Well the beauty about gray is that there are tons with blue and green undertones that are quite beautiful and would add life to the space. Or you can get blue that is grayed down to keep it from looking too stark. I googled a search using Almond tile with gray's in a bathroom and found these, all of which I think are lovely. ETA I also hated the oak cabinet in our guest bath. Painted it black and it's beautiful again. This is SW Oyster Bay I'm not sure of the color names for these, but they at least help you to get a visual.

Your tiles are in great shape and should be easy to work with. I would embrace the period and have fun with it. I'd look for a pretty shower curtain that incorporates the blue and stick with a white close to the color in the floor tiles. I would keep fixtures in chrome, which are period appropriate for your bathroom. https://www.homedepot.com/p/Home-Decorators-Collection-22-in-W-x-28-in-L-Framed-Fog-Free-Wall-Mirror-in-Silver-81168/205577496 Embrace the time period in the bathroom with a light style that is from the same period. https://www.amazon.com/Nuvo-76-277-Diamond-Channel/dp/B002OMJBNO This shower curtain would be great in your mid century style bathroom. https://www.opensky.com/avlolo/product/mid-century-modern-retro-drop-shapes-in-shower-curtain-60x72-inches? Since you don't have a lot of room to hang towels, I would add over the door towel hooks and something like this over the toilet to store towels. https://www.wayfair.com/home-improvement/pdp/dotted-line-demi-wall-mounted-towel-rack-w001991980.html?piid=