maybe not so boring!
I would have problems using all pastel's to make a baby quilt. This is just a quirk of mine, I like to make them "simple and BRIGHT"! My favorite "boy baby blankie" so far, was cotton Camo and a bright orange tiny floral. I made simple drunkards path pattern and quilted from corner to corner, ignoring the curved pieces. I did the back in a deep brown flannel. And he's 2 now, it's still his go to blanket at night or nap time! Mom was going to hang it on the wall, she said it was too pretty to use. Happy to say, the Dad told her Baby gets to use his blanket, it was made for HIM to USE!
If your friend has gone to the fabric store and purchased a pack of precut fabric, see if they are open to adding a simple background fabric. Remember, all background doesn't need to be black or white, it can be any shade that coordinates or contrasts with the primary blocks! And it could be skinny strips between the "plain" nine patches! I agree that making sure the construction would please the "quilting teacher" inside you is a great idea! Keep the corners perfect!
Of course, I wanted to attach a shot of the orange and "camo" quilt, can't find it. Here is a "pancake" car-seat quilt I just finished for a friends first grand child. I did use PINK, but not much of that was "baby" tones! Have fun and enjoy adding to your own stash!