I think your playroom/office will be bright and cheery with this rug as the colorful star of the room! You could do simple white walls, or a light silver would be amazing to contrast with the pink, while still being a light, bright neutral. For upholstering the benches/doing shades, that would depend on what color walls you went with, but I think a grey/silver tone-on-tone between the walls and fabrics would go really well with dark floors, black furniture, and the bright, bold rug :)

Side note, I really like this photo with a pink rug:

I love what they did in this bed room and I think it would work with your beautiful rug: Posters guessed that the lilac color is and the tan is

I would pick one color from the rug to highlight for benches, but keep the lamp shades white. How about blinds with gauzy white sheers for the windows? Simple prints like ones in the bedroom would look good, as well as, black and white matted and framed photography.

Good luck.