I think you need to post a plan, so that maybe some of the kitchen planners can have a go. If you purchase base units to use as shelves, some with doors and drawers, you need to find a kitchen manufacturer that offers colour co-ordinated carcasses so that everything matches. ( Inside the cupboards and out so that you can have cupboards with no doors just shelves ) Such as DIY Kichens amongst others DIY Kitchens I'd start there, to see what colour carcasses you can get, then get the kitchen planner on the job.

Hi, I'd look at the other colours which will be utilised in the room such as flooring, doors, etc and Basey decision on that. Personally, feel that both oak and white could work. Oak brings about a nice Warmth when paired with grey whilst white is a more contemporary option.

Unless you particularly like the desaturated look of all greys, my instinct would be to go with a more natural shade of oak for the flooring. https://www.howdens.com/joinery/floors/flooring/vinyl-flooring/quick-step-livyn-single-plank-natural-oak-luxury-vinyl-flooring-2105m-pack-sdh3680 Possibly even this; https://www.howdens.com/joinery/floors/flooring/vinyl-flooring/quick-step-livyn-single-plank-dark-brown-oak-luxury-vinyl-flooring-2105m-pack-sdh3684 for more contrast. The shelves are fine in whitewash, painting them may make the room feel smaller. Its better to let your items on display be the focus, than the shelves themselves. The darker bifold look more modern, and add extra dimension to the space. Depending on where the other window is, and how out of place it may look from the outside, you could replace it to go with the doors, or have the internal frame painted to match.

That’s good they will give you a sample. Had a quick look on their website and it looks a beautiful colour and I can see your dilemma. It has a grey-brown hue similar to F&B’s Mouses Back, well on my screen anyway! Were you able to view a kitchen, or at least a door, in it? Im not sure I would choose a kitchen just from a photo. Second photo is F&B’s Mouses Back.