I'm gonna ask you a question? Do you have a favorite block, you said you were leaning towards the pinwheel? Then make it girlie!! I've done 4P with solid white in between and for one of them I hand-quilted designs like ducks, etc and the other 4P was done on point with little pink rosettes tacked down in the center of the white. Hate to say it, but IMHO, this is where the matterial makes the quilt.
Enjoy!!! Babies are a wonderful gift!!!