Not sure what you need help with? Layout for the floor or walls? And why can the 'marble' tile not go in shower or above tub?

The “marble” is too thick for the wall. I am debating on whether or not I should switch the colour of the subway tile to white. Should I frame the tub in subway or floor tile? Should I do subway halfway I’ll the wall or to the ceiling? I’m worried kt be too busy

You might be able to ‘see’ what you like by searching ‘corner tub’ here in Houzz. Your ideabook for bathroom has none. That search alone should help you figure out what you prefer.
https://www.houzz.com/photos/traditional-master-bathroom-traditional-bathroom-chicago-phvw-vp~461812

That grey looks very 'flat' against the marble. Are you sure you want the marble on the floor? You should be able to get a ceramic tile with the same marble effect. I'd be putting that in the bath area, and I would seriously think of finding a floor tile with the fabulous black and white pattern effect of your accidental background. :)

If I understand correctly, you want to use the subway tiles for the shower walls, tub surround and tub deck? And are considering the marble porcelain tile for the main floor and the tub facade? I wound not mix them on the tub. Do the subway tiles you've selected come with all the trim pieces needed? Why can't you use the marble looking tiles on the walls?

White tile on wall would provide more light and contrast, but think of someting other than subway for the bathroom. So many many pretty patterns in solid white to add some oomph. Gray is so, well, tiring. Like a cloudy day.

I don’t like the grey subway. I would do the marble on the floor. White subway in the shower. Frame the tub with wainscoting type paneling similar to the pic below. Marble mosaics that match/complement the floor tiles above the tub.