Rather than a fusible, I would sew them into a quilt with another light weight fabric and quilt each block enough so that the quilting reinforces. There are plenty of ways to attractively quilt an embroidered block. I have seen many with cross hatch going right over the embroidery and it looked great. But if you don't want to quilt over the embroidery, this quilt is a good example of what I am talking about.
Birds of a feather finished
In this link I show pictures of the embroidered blocks both before and after quilting.