HmmMMMMmmmMMMMm. They would have an interesting relationship, that's for sure! Maybe Nadia's parents are willing to overlook the Flamels' "blemish," but I think Nadia is convinced Fabienne is sort of crazy-pants, and low-key likes it. She doesn't care about bloodlines, but she finds people interesting, and because she's got a big mouth and a lack of a filter, they've probably had altercations, at school and at functions outside.
We did have sort of a bitter dispute between Fab and Rosalind (I'm not sure about the origins) but would you like to work that out again?