You are doing the right thing by thinking about all three elements. There are so many grays. I would wait until the counter is installed, then choose the tile.

I like all your choices.

Did you think through the undertones carefully?

You have copper, which is very warm, nickel which is cool with a blue cast, sort of a blue grey light colored backsplash, walnut which can be warm or greenish depending on the stain, and a marble look quartz which in that picture looks cream but in real life is probably a cool white ground with grey veining. I think these are fighting with one another.

I would probably try to align the elements around one undertone. Pick the thing you love best- lets say its the copper hood-- and choose a warmer grey backsplash and more warm toned counters. Jury is out on the walnut because it might or might or might not be the right undertone- hard to tell from the pics. I would choose hardware that looks more natural with the copper-- definitely not a brushed nickel with that hammered, shiny copper.

Sometimes its hard to resist the urge to put everything you love in one space. It can seem dull to just pick one tone or one type of finish and go with it. But it will make your space look much more coherent.

I don't find polished nickel to be cool at all. The walnut has a clear coat and is not stained, so I don't think it could be anything other than warm. I do think the back-splash may be too cool for the rest of my picks, so I will wait until everything else is installed as eld6161 suggested. Thanks for the feedback.