Babies love black and white. I collect B&W fabrics specifically for baby quilts. You've had tons of suggestions, and some gorgeous quilts have been posted. Sounds like the mother really wants to display the quilt all the time, which beats it being "put away" somewhere and never used. To appeal to the baby, I suggest the B&W, no gray, and good lines of demarcation between the pieces. They love the bright colors also. I frequently do double-sided baby quilts, a panel on one side and the sampler blocks in B&W on the other. Just adding my 2 cents.