Don't know about mixing fabrics, but do any of your bridesmaids have their dresses? They wold be neat to incorporate in the quilt. I would do all the pieces in your gown and a bridesmaid gown. If you had lace, beading, covered buttons, they would be neat to beautiful to use too. You could always use fusible interfacing or another type of facing to stabilize the fabric. Pinterest had a quilt link that was made from bridesmaids dresses. It was beautiful.