It all starts taking shape..))I must say I spent like 10 min trying to see the cream tile you found...)) Finally discovered it, lol As for the back splash-my contractor wouldn't let me get away from some sort of back splash..especially it's not a tiny powder room, since it has a bathtub..Activity will go there, the wall should be protected. Unless-another possibility-you take your mirror right to the top of your vanity counter. Not everybody's a fan of this look, but it is an option. As for mosaic question, I'm really not sure..color wise might be fine, but I've no idea how two different materials will work together in application..one is porcelain(or ceramics?), other is stone..I'd be hesitant to order at least until I talk to the tile guy. It's not only color, it's texture, width, who knows what else.. They didn't have bigger tiles in this soft cream, the ones you were contemplating, 4 by 10, right? Still don't know why I prefer this size in your place..maybe more modern look, less grout? Are you going to use a shower curtain or a glass surround for a tub?

Frankly, nobody should purchase a marble top for a bath vanity. This is always a match/ blend issue as tile and slabs come from different sources. It's virtually impossible. Marble baths benefit from a simple plain quartz top on the vanity. Knock yourself out with marble everywhere else. Porcelain and the real deal stone will ALWAYS disappoint, Every. Single. Time. No bath should be demolished until every needed material has been selected and checked for compatibility. Or this delay is also a guarantee.

My opinion will be biased because I have very similar tile in my master we redid 12 years ago. 4" squares on the diagonal for the shower floor and 12" squares on main floor and up the shower walls. Coincidentally we are in process of redoing my kids' bath the past few weeks (it was also redone 12 years ago) because a hard-to-find leak in the tub prompted us to consider replacing it....which then brought about the issue of replacing the tiled tub-surround that would be damaged...and we would also have to try to retile some spots on the floor because a new tub would be a smaller footprint leaving some bare spots once old tub was pulled out. My point is that we also had to figure out the whole, "do we do an updated 'patch job' to save a lot of money, or do we just gut it and accept the cost as the price of being at peace with it/enjoying a new look and improved function. Right or wrong...which is always a very subjective thing....we gutted it and I'm thrilled. I was not interested in painting my cabinets just to have them have peel-issues due to steam, and we also got rid of the tub altogether and opted for a stand-up/walk-in shower for my older kids. Resale was considered on this issue...but by the time we move, someone can either love it as we've made it, or we will price the house with an "allowance" in mind. The old space had hot-chocolate colored walls and 'slate' porcelain floor and tub surround...an overall warm and cozy feel but also tired and dated. The new space is a porcelain 'marble' hex with white subway walk-in shower that is awaiting glass doors...an overall calming feeling that is also bright and fresh. I now actually wish SO BADLY that I was able to redo/retile MY whole bathroom (tile similar to yours). And there's nothing wrong with my bathroom, and a planned paint job on the walls will help me like it even more...... In my kids' bathroom, however, even unfinished with the floor and shower tile installed just waiting for the rest to come together (waiting on backordered tile base moulding) ......... I walk in and just smile and breathe deeply because of the way the space now makes me feel :) So my very biased vote is to gut it ;) ;)

I would choose a tile paint that would cover ONLY the red. Find a colour that would work for the bathroom (with floor pattern as-is) and then go ahead and paint JUST the red. But that means you would HAVE to change out the light/plug-in facing to the same colour (or match the wall tile colour). Personally (because I am cheap and lazy) I would look at large throw rugs (no backing...just natural fibres...you have in-floor heat) to cover up most of the floor. By leaving a bit of the red peeping out means you can leave the switch plates alone. If you are moving in 4 years, you can reassess in 3 years. Remember: if you are moving in a short amount of time, you are not the 'owner' you are designing for. You are trying to design for someone else. Someone you do NOT know. That's tough enough on it's own.