Thanks so much! We struggled a lot with the choices, but we're happy with how it finally came out.
We found the Rustico Mocha looked darker in the design centre, just seeing one tile. Once it was installed, it really doesn't look very dark. It's just dark enough that it brings out the cabinets, without too much contrast. We picked it in March, and it was installed in October, but the colour didn't change during that time (though I know it has in the past, so anything's possible).
The quartz is Victoria Sands. It ate up a chunk of the upgrade budget, but we're SO happy we went with it. Though the price was pretty fair, especially since it includes the upgraded faucet and undermount sink.