You need to respect the mother for caring so much about the stepdaughter's feelings. I would have a hard time making a black and grey quilt too, but would try to accomodate the Mom's wishes. Is there any fabrics in those colors with juvenile designs? Perhaps old time cartoon character prints would come in these colors...Good Luck with this project. Maybe you could make 2 quilts if time permits..one for the crib in the mother's choices and the other for the "security blanket" that the child could carry around as he gets older in your choices..