You could use the pastels for sashing, another for trim for the diaper bag. I never had pastels for my first son's nursery but I had every color including black. It was a zoo theme wall paper with animals in cages and only enough for one wall. Got goldish orange shag carpet remnants and attaché them to the floor. My husband at that time wanted paneling (ugh). We worked with what we had. It really was cute. The white in the wallpaper just helped to balance that child's room. I think you'll be surprised how well it will turn out. I saw a knock-out nursery done in grey and black with pink and yellow accents. Yep it was a little girls nursery and she was able to grow up with it. the ceiling was a very light grey with white trim molding. Stunning.