Your little girls are ADORABLE!
My daughter has a similar PWS except she has patches on her head and it extends on to her neck and chest. She had and MRI of her brain with contrast at three months old and SWS was ruled out. She was under anesthesia for that so we felt OK that she would handle it well for her first PDL treatment at 6 months. She did and was at home that same afternoon jumping around and laughing in her exersaucer! It was a wonderful relief to her very anxious parents.
I will try to attach before and after pictures of her treatment as well when I can figure out how to do it. I know seeing what we could expect helped us mentally prepare for her first treatment. Her second treatment is next week already. Time flies!