I cannot advise on grey owl, but I had to deal with warm woodwork similar to your color, a warm-toned brick fireplace, and warm "tweedish" carpet that I was not ready to replace in my family room. I painted multiple sample boards, and the one that looked the best in my space was Sherwin Williams Worldly Grey.

Will a light gray clash/look strange with the warm tones of the cabinets and floors? I feel like the only other option is white, which I really do not want to do.

Gray is not a problem in and of itself, but the one you have chosen has cool undertones that may not be flattering to your warm woods. White is not the only other option. A warmer gray can absolutely work.

Below is Owl Gray; its green undertones could make your floors look orange. Compare that to the greige below, a warm grey beige from Farrow and Ball that makes your floors look mercifully brown.

These hues are not that different, but their effect on your space is huge.

For backsplash we are looking at marble tiles of some sort (either brick pattern or herringbone).

If you can wait to pick a bs that will give you the option to see sample tiles in your space with your materials in your light. That said, nothing makes faux marble counters look faux-er than a real marble bs. In the image below, the bs looks like the real thing (because it is) and the counters look like plastic. It's also a lot of "stone" look in one place. That said, people do it all the time. Google your counter and maple cabinets and save images of kitchens that you like. It may help you find a look you love.

I just painted my bedroom Sherwin Williams Stone Isle. I feel like it is a nice light Greige. I actually wanted a cool grey, but the fabric that I found for my curtains was more greige so I matched that. The Stone Isle seems to change a lot in the light which is really cool. (or not depending on your opinion) Sometimes it looks beige, sometimes it looks grey, sometimes I can't tell the difference between it and the white on the ceiling.

We have maple medium dark stained cabinets in our new kitchen with a tile floor and we chose SW Agreeable Gray for the walls. It has a bit of tan in the gray so it works. I wouldn't use a very gray Gray if that makes sense.

Look at BM Balboa Mist or SW Agreeable Grey.

OP here, I appreciate all the feedback!

BM River Reflections is my cabinet color - it's a nice, warm-toned grey.

I need to check out stone isle. I love chamealon type colors and need a new color for my sitting room.