mMF in Legendary Beasts help with Familiars?

a couple of years ago when I asked a question about how to define Legendary Creatures, this seemed to be the uncontested answe

now wondering, in addition to how this MMF affects spells, is how it might influence Familiar Bonds.

I am assuming magicians other than the descendants of Bjornaer may get an MMF mechanically identical to Bjornaer's
And one of the potential Familiars is a hippogriff.