Daddy Dudley -- what a fun idea; I don't think I've seen it before. I like the fact that he and Millicent are attracted to each other's larger size and to interesting gender incongruities (like the fact that for a big man, Dudley has a soft voice, and that Millie does not have soft hands).
Perhaps my favorite part:
She laughed. "Spoken like a true Slytherin." "And that's good?" "The best."
A refreshing take on the whole "evil Slytherins" trope.