Can you post a picture of the counter and the rest of the kitchen?

Start with white/gray then add a little hue of whatever color your countertops have

So is that green in the countertop? It's hard to tell with the lighting. If so, I would lean toward green, but I like color. White/cream wouldn't be wrong as long as it goes with the white/cream in the counter.

Beautiful space!

The cream/white will look a lot like your painted wall. There is a reason why you brought up that fabulous warm green... ;)

If you use those green tiles, I would try to use a color-matched grout. I know I differ from a lot of people here, but I find grout lines with subway tile (esp tiles that are so narrow) to be a bit much when paired with a busy counter. But that is, again, my personal preference. I like color and I dislike busy.

What a fabulous choice for such gorgeous cabinets. Well done. That would have been my choice too. I'm white/gray/beige averse. LOL.

The use of a flexible vinyl range exhaust duct is forbidden by the International Residential Code and hood installation instructions. Someone owes you an explanation.

VENT A HOOD installation instructions