I would square it up and add a plain navy blue border or a navy inner border and a red outer border. Then I would find a pillow panel from the 70's or 80's for a Raggedy Ann or other cartoon type doll (clown, puppy, Snoopy, etc.) in those colors. I think those are about 18" tall, so it could go right in the middle. Since you shop estate sales, it wouldn't be hard to find one.
In the end you would have a colorful toddler quilt.
As for those extra pieces, I would disassemble one enough to make a border for a label and forget the rest unless you wanted to make a small pillow to go with the quilt.