I would use a heavy starch solution instead of fusible to stabilize the fabric. I'd cut the nightgowns apart in order to have flat pieces of fabric to work with, paint on a 1:1 solution of Sta-Flo liquid laundry starch and water with a large wallpainting brush, toss in the dryer, and then iron with steam -- all before cutting the fabric.
The pattern may depend a lot on the nightgown fabrics themselves. If they are all pastels with small printed flowers, you may need to add some white fabric to set off a pattern with lattice or sashing. I think a simple 4-patch would look nice this way, either straight or on-point. I wouldn't necessarily make each quilt in a different pattern; even with the same pattern, fabric color placement will be different.
I personally don't like putting a photo on a quilt. I would put a label on the quilt, though, with the name of the person being remembered.