the cabinets are way basic. You will eventually want better.....altho they are okay for what they are. You are spending generously for the new counters. Be sure you feel it is worth it. I might go ahead and lay the new material on the island only. ….nice upgrade..and keep everything else. Give yourself some new hardware. Furthur down the line you can redo the perimeter...and lots of things will work with that material on the island. Keep the floor color...the issue that will become more important is your perimeter.... [spending and deciding new floor color now does not seem prudent]….your colors and style may change. And by chance....when the time arises if the island gets re-done you have not overspent if you only lay the new top. The piece you picked will give the island a great new look ,and do a lot for your space for the near future.

Your cabinets appear to be natural maple. Oak has a much more pronounced grain. Maple does tend to yellow over time.

As for floors - I tend to like the natural wood tones or only slight staining. Darker floors show more dust and scratches. Some however prefer darker and don't mind keeping the Swiffer handy. You floor looks like a natural or possibly "spice" prefinished oak floor. These can be a little more to finish because it takes extra work to remove the factory finish, but they should be smooth and look really nice when they are done.

Be aware that counters with large format design can be difficult to seam well (get the design to match across the seam) especially in a counter the shape of yours and may require more than one seam - a countertop person could tell you for sure. You may need to buy extra material to get any kind of a match on the seams. I would consider a less bold pattern. Most warm woods do not work well with cool grays. However, the more yellow tone of maple does seem to help it work with grays, but be careful of overly cool toned countertops.

Here is a warm wood kitchen idea book - perhaps you will get some ideas:

https://www.houzz.com/ideabooks/75202366/list/wood-kitchens

I agree, your cabinets appear to be maple or birch, maybe...it's hard to tell from a distance, but a closeup of the wood could help to identify.

My thoughts about that light marble look is that it's very trendy right now in new and fully remodeled kitchens with updated cabinets and other features. While I like your cabinets perfectly well, I think I might not want to mix them with a countertop that is so 2018 (and 17 and 16, etc). It might just emphasize that they are not the latest on trend, as the countertop is. Newer hardware, pulls and such could really update them, though.

Personally, I'd like a little more contrast to the color of the cabinets for your countertops (this might be marble or marble look, too, though:

I think your right about contrast on the floors; either go natural or darker than what you have.

I have water-popped provincial stain on hickory; it is a medium dark floor which people would probably warn about showing every spec. Personally, I do not think it is too bad, and a Roomba has become my new best friend...easy!

I think there is enough contrast between the floor and cabinets currently. It's not high contrast, but I can definitely tell they aren't the same color. Is the space between the island and the outside corner by the dishwasher as tight as it looks in the picture? I ask because spending money to make cosmetic improvements when there are layout or other structural/substantive issues is usually inadvisable (better to save the money for a more major overhaul). The apparent narrowness could just be a trick of the photo, though.