The best position is whatever works for you and your daughter.
I doubt the colonoscopy is the cause of Catelyn soiling her clothes. Please do not let your daughters use enemas in order to have a bowel movement. (There are emotional issues here and I know you probably know this.) Figuring out the correct diet for them will take care of their problems. It all comes down to what they put in their mounth. I know this isn't easy. Plus they have a mind of their own...
They will heal, but this will take time. Are you familar with this product http://www.herbdoc.com/p24.asp I take his Formula #2.