Besides the fact that both Westeros and the world of Disney Princesses seem to be pretty scant on brunettes, the rose imagery at the heart of Beauty and the Beast made this match-up (with the Tyrell house sigil being, of course, a flower) pretty easy.
So... according to this Beast is Joffrey xD
Love the rose similarity too
Margaery and Belle also have a thing for Beasts, because I'd say that Joffrey is a little monster.
I think this one's my favourite..
and both maergary and belle are very smart..
And they both marry beasts, of course.