Super book shelf quilt! The waving is probably because the edge stretched when you put on the binding. I usually iron my quilt edge after quilting and use a large stitch and my walking foot around the perimeter of my quilt before adding binding. This lets me see if it is laying flat with the stitching and if not I can pull the bottom thread a bit before adding the binding. The stay stitching also prevents me from stretching the quilt edge when I sew on the binding, you also want to make sure you are just laying the binding along the quilt as you stitch neither stretching it or putting too much before the needle.
With that being said, the only way to fix the edge is to remove the binding and try again but with the Minky back, it may not be any better the second time.