Hestia is a saint for putting up with Petunia and Vernon. A saint, I tell you. And what a lovely surprise 'Dung turns out to be! He's on to himself, which is always fun.
And Dedalus is a delight. I can't decide if he knows about Dudley's crush and is being coy, or if he truly doesn't know. Either way, what a wonderful character you've created.