I am glad you have talked about this with her. When I was doing evening wear, prom dresses, etc., (with lots of training and education behind me), I had more than a couple of brides bring me dresses that other supposedly "professional" seamstresses had all but ruined. Luckily, I was able to salvage the messes brought to me...and they were not always easy. As Scissor Queen said, satin is not for a beginner. After 25-30 years of working with "slippery" fabrics for evening wear, or lingerie, my suggestion would be to think about other options to include these dresses in making memories. Perhaps parts of each could be used to make a ring bearers pillow, pew bows, toss pillows for the wedding bed, or ???????????