Don't spend the money to match the exterior finish of the cabinetry on the cabinet interiors, you want the interiors to be easy to clean and a light material so you can see what is inside them. No one will notice or care if the interiors match the exterior (these days it is pretty much industry standard that they do not match) If the cabinet doors have glass fronts then definitely match the exterior or use a pop of paint color on the cabinet backs.

What soft furnishings do you have. You could pic out one or two colours as an accent colour and use that as your Base for the curtains. I currently have cream hessian walls and have a duck egg blue and chocolate curtains. I'm currently making matching Oxford cushion covers for the settees . If you can't find what your looking for ready made buy the fabric and have bespoke curtains made for you.

Well it depends on your wall color as well . since you have such concrete looking floor I would recommend you can chose any electic color like lemon , orange , yellow to give a bright look and uplift room mood or chose any pastle color of your choice for subtle feel . :)

I prefer shades of brown ..blends well with all colors.