How funny. I just renovated (on a budget) my small kitchen and added exactly the slate look in tiles you have, though they are in fact porcelain. And I placed them throughout the house for continuity. The tiler asked if I was after a retro hippy look but it doesn't look like that at all. My cupboards were the same colour as yours and I utilised the bones of the kitchen and had the doors and Benchtops changed only. I also have plenty of light in the kitchen but chose white doors and as I was on a budget I chose granite look Benchtops, they are very serviceable and it looks great. The blue backsplash was the colour lift and here you could choose any colour to your liking. Basically the kitchen ended up with white cupboards and appliances other than cooktop, with the stainless cooktop and coloured splash back being the focal point. The paint colour are: whisper white walls, integra splashback, white ceiling and for increased contrast I used the same white above the splashback on the rear wall. I would consider painting out the brick but leaving the texture.

I work as a colourist and the easiest method for a upmarket look is to choose an exact colour to match one of the colours in the tile. I would take the tile to a paint shop and get the colourist it match exactly one of the greys in the tile. Make the depth of the colour a light version. All white walls are on the way out. Lappatto tiles usually have some texture as they are semi polished. This is the latest look in tiles as they give a shine without the maintenance of polished porcelain which had been in. They are usually less slippery than satin or polished tiles depending on the brand.

This is a very personal choice as dreamer mentioned. You can order tile samples from tile cloud or TileMall for $15 for 5. Pick some options you like and put up in the kitchen next to the other elements. You will soon know which one you love the most 👍🏻

I'd say a charcoal -- you don't want anything too white or grey IMO , or it will be overpowering in an underwhelming way , and most other tones either clash or will look cold , or both .