I have been thinking about this question since last night. What about putting applique bees or dragonflies on the holes? It would enchance the repairs with a detail. Sometimes I have seen these in stores on the notions wall. No matter what you do it will show so why not make it a design detail? As for the tears on the back, you could just add a whole new backing over the old one, quilting in the ditch around the blocks. I agree the holes will need to be filled with little pieces of battting. Charsue's idea of printing the design on your own muslin to match color is inspired, it may not match exactly but will probably come closer that anything purchased new.