A dark floor isn't inherently a problem, but I'd test the exact tile rather than judge from the rendering. A nearly solid, glossy dark tile can show dried water drops, dust and light-colored lint; a matte tile with some color variation and a medium-toned grout is usually more forgiving. Take a sample home, let a few drops of your tap water dry on it, and see how it looks after your normal wipe-down. Also check that the specific tile is rated for a bathroom floor and has a finish you're comfortable walking on when wet.

I'd choose the floor and vanity from physical samples in the room's light before settling on the shower color. The light oak could work nicely with a muted green, but the undertones in the actual wood and tile matter more than the AI image. Since the sink spacing already bothers you, I'd measure the usable counter between basins and the drawer clearances before ordering the vanity; that layout is harder to change later than paint.

I have charcoal slate tile from Brazil on my bathroom floor (4x12 tiles in a herringbone pattern). I don't have any issues with having a darker floor. My shower is all Carrara marble + there is a 42" high Carrara marble surround for the freestanding tub.

The vanity is rift sawn white oak - 83" wide (sits inside an alcove) and has only drawers - no doors = great storage. It is a floating vanity - however, it's only about 10" off the floor.

My ceiling is pretty tall - there is a slope at one end (starts at a little above 9') over the shower area + first part of vanity across from shower - then it is 11' high (at least 2/3rds of bathroom has a flat 11' ceiling). I have one tall (large) window (on a wall with 11' high ceiling) in the bathroom that provides a lot of natural light.

I have three sconces on the vanity wall + two mirrors. I have a light fixture over the freestanding tub + a recessed light over the shower. Also, there is lighting under the vanity - it has a motion sensor = nice for at night because I don't have to turn the bathroom light on (there is a separate WC with a light - but I don't close the door - just close the double doors into the bathroom)

I love my slate floors! They are gauged and honed tiles = pretty uniform + smooth surface even though natural slate.

a dark floor will show dust and hair, but IF you have a window for natural light and keep the walls light a dark floor could be a statement.

I'd look for a soft green/seaglass tile for the shower rather than gray. Gray has been done and over done.

The vanity is great, especially the drawers. will complement most tile options. Keep the colors simple, add interest with towels.

look for a White paint with a undertone of what color you want, not an actual color.

The undertone will give you enough color in a small space especially with low light.

Are you shopping for everything through Home Depot? Behr® paint colors?

Re: natural light--there are 2 windows in the bathroom. We wide blinds on them and the let in a little light. There bathroom faces the street, so we can't open them, but there's enough light that I don't need to turn the light on during the day--or even at night if I get up to use the bathroom.

Good idea to bring a sample home and test it. And I'm definitely using something rated for a bathroom floor. I've seen a large hex tile with some variation. I'm not looking for hex specifically but wouldn't rule it out.

For the shower, I'm trying to get something dark enough to use at least a gray grout rather than white. I don't like beiges and tans in general, so that's why I'm leaning toward a light gray. For green, I ordered a sample of this tile in jade and azul but they only sent the azul--twice.

https://mmgmarble.com/product/porcelain/dream-onyx-cross-cut-porcelain-tiles/?attribute_pa_finish=honed&attribute_pa_choose-color=jade&attribute_pa_options=24x48-tile&utm_source=pinterest&utm_medium=social&pp=0&epik=dj0yJnU9LUVEMHJ5Z01sMnNQZFpmYi01V2xCdEpDNFhnY1FzNzImcD0xJm49UFJ0dGNxMG16a2xncDd5VmlnY2dIZyZ0PUFBQUFBR3FlQ1Nv

But something like that, if it was a bit more muted might be good. But so far it only exists in my mind.

I'll be using 24x48 tile to minimize grout lines.

@dani_m08 I looked at a couple vanities with only drawers, but between the pipes and the drawers not being that deep/tall I don't think I'd be able to store some of the taller cleaners and bottles I have.

https://www.wayfair.com/home-improvement/pdp/ackland-ardena-24-in-x-48-in-matte-porcelain-stone-look-floor-and-wall-tile-mvp11615.html?piid=98041748

this pallora color is interesting.