I like the Carrara better than the limestone--it's less busy. Just make sure that you inspect the actual lot of marble, since it can vary greatly from a showroom sample.

BTW, I love your Polarstone quartz, and I'm very picky on marble-look quartz. Most of them look fake to me, and this one is very authentic. Is that your actual slab? If not, make sure you see the actual slab before they ship it. Man-made quartz can vary from lot to lot as well.

I like the Carrara better than the limestone. I know many people warn against putting natural stone against quartz. Often they just don't match but look like you were trying to match them. So I wonder if you would consider a Calacatta herringbone tile. It tends to have more grey veining than the carrara and might look more "intentional" than trying to match the carrara to your quartz.

Whichever you choose, buy enough extra of your tile so that you can pick through the sheets and find the ones you like the best. At the end of your job return the remaining (check with your tile supplier first for their return policy and beware of restocking fees). That way you won't be stuck with some tiles that are a very different colour. See this sample: calacatta-italian-marble-herringbone-mosaic, some of the veining is decidedly grey, but some if taupe or even a bit rusty looking. That would not please me at all.

Also, although I don't think you asked, I'd lean towards the lighter grey grout. The lightest one in the limestone picture. You're showing what looks to be black grout with the carrara and I think it is too much contrast.

Hey Morgan! What’d you end up deciding? Do you have any pics of your kitchen? We’re also leaning towards Olympia for the countertops!

I would go with solid white subway tile in a white which matches the background color of the counter. If it doesn’t match it will always look “off”.
The tile layout matters less than the color match. I do love herringbone.

I would go with Carrara Gold marble tiles or, even rather, use the same quartz as the backsplash -- it would create such a dreamy and airy look.