A lot of the paint companies have visualizers you can use to upload a photo of your space and then "paint" the space with their color palette--I would definitely take advantage of one of those programs because on my monitor your flooring looks like desert sand and your walls look gold, and I'm not sure how accurate that is.

I don't see it as a dark/light question, but rather cool/warm..travertine and granite lie in different realms there, so it seems.

I wouldn't overhaul everything to change that, because not a lot chances it will help in some overwhelmingly great way..if yes, it's already easier to change the flooring(maybe)

I would paint creamy warmer white..

or there are some pretty purplish-brown colors..if you want to repeat the travertine..when something is repeated it gets less emphasized, in a paradoxical way. It'll be hard to find such color. that will work with the counter too. and the room will be darker. Interesting direction to take, but easier to go with creamy white as suggested before

What finish the faucets will be? .

and I'd find a nice runner for the floors as suggested

And I might go for knotted wool one too..it's very durable, withstands moisture well, and elevates spaces..and because it's small it's affordable.

(that's what I did to cover my own travertine..or rather-travertine-like porcelain tile. Helped my mental well-being.

I did go with a very simple vanity surface though, so didn't have to take it into account)

And in terms of accessories-you can tie it more, with smth wood..say a tray or a storage thing-y..or warm metal..

Styling goes a long way in cases like that

Your fantasy brown is beautiful..and yes it's often hard to imagine how whole slab will look in your space in yor light..one tries of course, takes samples and all, but slabs are the most difficult of them all

I almost think a darker color would tie it all in better, but then, I'm no pro.