The second bathroom with white vanity is already leaning in farmhouse direction.

The first bathroom, maybe bring in another light fixture over vanity (I can’t really tell what is there now, too much glare in photo). Plus it looks like mirror or mirrors will be installed, so you can bring some more of your style in there. If you wanted lighter walls in that bathroom, maybe something like Benjamin Moore”s Ballet White or Swiss Coffee. You can try some samples. I like BM’s Natura line. You could also consider painting walls in that bathroom a light pastel blue.

Other than that, both are very nice bathrooms as they are. Maybe accept them for that.

My mother has a similar bath in her condo, we painted it BM Venetian
Marble 2114-70

In the master, I think the only thing you can do is lighten the wall color. Paint out the dark cabinetry with the lighter vanity color in the other bath.

Other people might have input on this product, but Rustoleum sells a tile resurfacing kit in a few colors - white, off white, etc. I have thought about using this on my own 1970s square yellow tiles.