It looks like you could do a gray-blue too, if you change the paint color. I've been working in that color family for my bath remodel. This is Tierra Sol H-Line II Series in Denim. It comes in 3x6 and 4x16. It pulls the gray tones but also looks nice with the yellow tones. It reads slightly bluer here in natural light. Many of these gray-blues have a touch of green too, which you should avoid.

I'm not good at picking backsplashes, but yellow river granite is a beautiful stone, and it looks wonderful on your cabinets.

I just posted this on another kitchen thread yesterday

I was going to suggest the tile I had in my old kitchen. In fact I liked the tile so much, I used the same tile in a different color in my new kitchen. The color I'm thinking of for you would work really well. It's Jeffrey Court Sand Bar. What I like is the crackle finish to give it a slightly more natural look as well as the slightly darker edges. Here's an old picture of it in my condo I sold. In the photo on the Jeffrey Court website it looks redder on my screen than what it was in real life.

Is that your island that will be two levels? I would rethink that, but it may be too late. I agree that the blue paint needs to be changed. That brings out the yellow of the cabinets. I like the tile that mayflowers posted.

A bronze pencil liner might work with the blue-gray I posted but not with a true gray.

If you want to use a cream, Daltile Rittenhouse Square in Almond is a nice clean French vanilla. It doesn't have any off undertones. It looked nice with my Giallo Ornamental Light granite, which has yellower tones than the White Ice granite shown here. You could use your pencil liner and a blue-gray paint. You can find Daltile at Home Depot or Lowe's. I don't know the quality but it's a good reference color for comparison shopping.

I do not have the same countertop, but cream does look pretty with oak cabinets. Oak cabinets have some "movement" to them due to the grain and so does your countertop. If the backsplash also has movement, even if it is pretty on its own, the look will be too busy - no place for the eye to rest.

Make sure to either remove the microwave, tile behind and replace it or reserve enough tile to tile behind it later should you choose a hood rather than an over the range microwave. As a short person who does not like a crowded cooking space, I would change the micro for a hood, but you may have a different preference or want to wait till the microwave breaks down.

My oak kitchen:

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~110720042

A one tier island will give you more space & will open up your space more. It seems like a pretty small island, so making it a 2 tier don't make much sense. Looks like you have a pretty open concept, I would leave it that way.

We had a slightly different grantite, golden flower, and used a gray subway tile. This was from a big box store, as this was a rental, but you might find another nice tile in a similar color if you like the look. A cream would be nice also.