OSB board will do the trick. You need another photo for us to offer a species and finish. Natural finish (clear coat...water based polyurethane finish...NO oil modified) in a low gloss or satin finish on white oak with FLOOD LIGHTS will offer the same "look" as the poor photo. Beyond that, you will need a better photo.

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.

Both the laminate and flooring are beautiful, but I don't think they will compliment each other. The flooring looks to be red oak and as it's name indicates has a lot of red in it. The laminate has a rustic feel and could be imitation walnut which is very neutral, wide grained and has no red. I think the lam would be fine with the paint, but not sure about the floor color. Are there other options for laminate wardrobe? Or do you have an option for flooring?

Instead of the solid grey, you can go for sketches in grey with flashes of mustard/ yellow. Or, look up these links for wallpaper ideas https://goo.gl/images/OrCtY1 https://goo.gl/images/0ZpAmU