Brilliant! I love it when writers are able to make the politics of Rowling's world mirror our own -- you do just that, and the result is thoughtful and clever and utterly absorbing. I love the little touches of humour, such as the Snitch's thoughts on Quidditch (hee), and the development of their relationship with Viktor is beautiful (and slightly ironic, given the past you've given them both). Though I realised the Snitch's identity pretty early on, I didn't see the revelation of the other, hm, disguised character coming at all -- wow!
In fact, 'wow' pretty much summarises my reaction. Thank you for a great story! <3
(One thing, though -- may I ask about your rationale for making Norwegian the lingua franca of Durmstrang?)