The picture on the website is a very nice combo of vintage/modern

Computer monitors are notorious for inaccuracy of color so it is difficult to see what all is going on here. Looks like the floor is rather neutral. Of the colors above, I would paint the vanity the Suitable Brown or a more grey brown than red. Ethereal mood could be a good wall color. I would down play the pink and green as much as possible. If I had my way, I'd change the vanity top to a neutral stone that works with the sink color, can't tell if the sink is pink or neutral. Check into seeing if they can replace the glass in the shower doors, tooo much pattern. If not hand some simple solid towels there. You're in luck as that brass color is back in, typically brushed and not quite as gold : )

Based on the description of your home and your personal design preference, I would carefully remove the Kohler pieces and sell them or consign them. No sense in turning your self and your home into knots to keep something that simply doesn't fit your style.

If you should decide to remodel, don't paint the vanity. It's the one item that works well with your vintage sink.

I'd say your biggest problems here are the green vanity top and shower and the brass fixtures. I'd go with a new vanity top in a neutral color, closer to a biscuit (which I believe is the base color of your sink and toilet). Removing the sink without damaging it might be tricky though. Taking down your shower walls is probably bigger-budget than you're looking for, but if your shower is the same line as your lavatory faucet (Kohler Revival; I can't see your trim but it should have the same scrolled handle) then you should be able to swap in another Kohler trim without breaking out your wall. I really like the Kelston line, especially in chrome:

Lastly, I'd suggest taking down the shower door and replacing it either with a frameless door (more expensive) or a nice shower curtain.

Wow!! Somehow the colours you chose turned the sink from a bright pink to a much more subdued off white! It is modern, clean and bright. Such a dramatic transformation - what a fun before and after. Wonderful job!

ETA: oh my gosh, I just looked back at the before photos and see that your sink was never bright pink! Only the flowers were... yet my brain somehow thought it was all pink!