I made one using a block and a 4patch alternating and it doesn't use much. I also just sent one to Marilyn for the PICU quilts that didn't use much more than that, but it was just blocks. There is a pic posted in the group. HST's will work with very little waste and it will mix up your fabrics. You can get 24 5" blocks out of each 1/2 yard. You could easily make a baby blanket (top and borders) with 2yards and probably have some towards the back.
Good luck and let us know what you decide on, I'd love to see it!