Hmm, Draco, Snape, Dumbledore, et al. are definitely having a bad time as Harry starts bringing out some uncomfortable truths they'd prefer stay hidden. 'Twill be quite interesting to see how various individuals deal with the whole truth, baldly told. I rather suspect that Dumbledore is in for a great many more rude surprises over just the Fall Term at Hogwarts, assuming he survives that long; I suspect he's now wondering if "Shadow" could form a block with Harry to take control of the school? I reckon that'd give him a fecal hemorrage. Yes, even before the other schools arrive, this year is going to be highly "interesting" at Hogwarts.
Oh, I did love that delayed action splinching curse on Umbridge, that's a delightfully devious way of disposing of her early.