Since the tile is vinyl, then it won't be so beastly to remove. If this was my house, I would tile because it's not that difficult, really...we usually rent a wet saw...There are some beautiful floor tiles around at reasonable costs. You probably want a wood look tile in gray. Fortunately that's popular and popular is usually less expensive and easily available, so win win. I love your paint choice and I think you should stick with it. Paint your cabs white or whatever color the shower is (we're using Benjamin Moore Advance after trying others. It goes on well and gives a good finish). If you have large builder grade mirror, I would keep it so you have more light bouncing around. They sell frame kits for them so they look less boring. I don't know what your lighting is like, but using led bulbs will make a huge difference. Personally that would do it for me to be happy for quite a while :)

Be happy you have a blank slate! You don’t have awful colors to work around, you have neutral. So often people write Houzz with the opposite problem-tiles with horrible patterns, walls with clashing colors, floors that fight with the rest of the room. Bring in lots of your woods with a coffee table in the living room, cutting boards and wooden utensil holders in the kitchen, natural wood picture frames for pictures of trees and colored leaves. The bathroom will come alive with brightly colored towels and a striped rug. Be an artist with this blank canvas and pick colorful things that make you smile and feel happy.

Bathroom vanities aren't that deep, usually about 21 inches. Kitchen cabinets are deeper, about 25 inches. Do you want it to be closer to 27 inches deep? Home Depot and Lowes have base kitchen cabinets in "unfinished beech". They come in multiple sizes, some for a sink, some with drawers so you can mix and match and they are ready to be stained or painted any color. They're about $80-$110 depending on the size and if it has drawers.

Ok, I had to look up what Japandi is and may not totally have the aesthetic down. But here are a few items that might combine to be what you are looking for. It's fun learning about a new style and I can see the attraction to Japandi. Floating sink in wood could bring in the Scandi look. You'd have to see what wood looks best with your flooring. Use black faucet and black for other fixtures in the room including lighting. On the walls I like the idea of grasscloth to bring in a natural element. I'd prefer a neutral, natural color so the black fixtures can pop off it. In this case I'd use a black mirror too. If you use a greyish or blueish grasscloth you could hang a natural wood colored mirror like above to contrast the walls. Put a simple piece of artwork above the toilet that has a lot of negative space and brings in some of the colors that you like. I'm not sure what your lighting situation is but I would go minimal and contemporary.