I love the house insults/stereotypes without the usual cliche of Harry pointing out the sorting hat offered him Slytherin.
And when McGonagall finally spoke plainly to the boys, I couldn't help wondering whether Snape had talked to her (maybe pointing out that Draco hadn't been at home) and the two former Heads were conspiring together to help their favorites.
I like this future you constructed, and can't help wondering what comes next -- how Draco's parents will respond -- both to the fight and the eventual revelation of Draco's relationship with Harry. And we haven't seen Harry's friends, so I wonder what they'll think of this.