If you want the wall and floor tiles to be the hero in your bathroom I recommend you keep the vanity very simple. The white cabinet you have will be least obtrusive with a 'white' top. I love the elegance of stone and man-made stone is generally more durable. Check out Caesarstone Organic White or Frosty Carina. Although Frosty Carina has more pattern than Organic White, it's quite discrete so shouldn't compete with pattern on the tiles. If the tiles are charcoal or a dark brown/grey then either should work. Love to see a photograph when it's finished, whatever you decide.

I don't have a bamboo benchtop but have flooring. There are many grades of bamboo based on hardness, which makes a big difference in how well they last - the best are as hard as hardwood. From memory, I think the lighter colour, the harder it is, because the process that makes them darker also reduces the strength of the bamboo. One big plus is that bamboo is fast growing and so you're not destroying old growth forests. BUT, some have formaldehyde added to it in manufacturing. You would do well to research and ask questions.

En-suite layout is fine, Looks like you have a double hung window with a slightly lower sill to the vanity height. . I’d put a stool in front next to shower screen. Update vanity and top and splash back, maybe lowering mirror. Could put a niche in the side wall if want extra storage. Could change mirror to a cabinet, even if it protrudes, mine does, A smaller basin would increase spaciousness and bench space. Can also increase depth of vanity, to 550. Replace floor tiles if you want but I’d leave shower if you want to keep costs down. otherwise retile to full wall height will improve look. Could add a pendant light over left side of vanity

The tiles will just mounted on the kicker of the vanity and then caulked at the bottom to stop water seeping under them. Shouldn’t be hard to remove. Just cut along the caulking first. They look like the match the rest of the skirting and shower. Are you retiling everything?