What a cute idea!!!!!!!! Here's what I came up with, Do the tights stop at the ankle (no feet)? To get more mileage out of them - and so that you can make a blanket for your DD too - trace them on a "shadow" fabric for the back. Draw feet or ballet shoes and place them in a ballet position. Position 1 on front and position 2 on back, for example.
Then you can make the same blanket for your DD out of the other side of the tights. Just a thought.......
Whatever you do, even if you just incorporate a square of that fabric in your quilt - it's a very, very special thing that you are doing.