Hi. I'd paint the dado rail and below in a darker shade of grey with a lighter shade on top. I wouldn't go too dark, maybe a light to medium on the bottom. If you wanted to add another colour for accessories try a deep turquoise or green. If you wanted more colour try a pale olive on the walls instead

Elephant's Breath would work as it has a violet undertone. It would accentuate the golden colour of the floor, if that is what you want. A slightly warmer colour with a complementary tinge such as Shaded White or Dropcloth may also be worth considering. I would avoid anything too warm as there is enough warmth in the floor.

Cashmere popular. Mine being fitted this week. I have chosen real wood worktop and upstand. Plain Glass splashback behind hob and oxide emerald green floor tiles. Just for something different. Walks mmm not sure……something muted. Small kitchen but bright! Ideas… don’t hate me re floor 😳

It could be any two cool greys from several sources but it may not matter. If you look at for example Farrow and Ball's colours it could be Ammonite and Purbeck Stone which could look very different in different settings or it could be Dimpse and Lamproom grey. In a sense, the most important thing is light because no matter what a colour looks like on a chart or an image, the light in a room can alter it dramatically. If you want cool greys then get one test pot of a pale cool as a starting point and go from there.