That it will be.
I was thinking that Dumbledore would have told them both that they had a 'Constant' that one thing that would work to calm them, or remind them their human etc. They could both think it is their respective fields of work, but instead it could be the Weasley brothers. As the theme of the Harry Potter books was love, I think it would be nice to tie in love for the girls, and that being the one thing that saves them. What do you think?