I particularly liked the portraits of all the various teachers you drew here: Sprout/Kettleburn was lovely, and I adored your Flitwick with his good humour and tact:
Filius shrugged. It was already Snape's funeral. Wasn't about to be his.
It was striking the way that Minerva - and by extension, the reader - had no inkling that her fascination and irritation with Snape was rooted in desire before she was confronted with that accusation. The way their relationship developed from there was fittingly unsentimental (perhaps even a touch too unsentimental for my own tastes - but that's the beauty of fanfic, eh? ;-) ), but some lines pulled at the heartstrings all the more for that backdrop:
Minerva had always considered herself a tough woman, so it was a bit annoying how heartbroken she'd gotten when the events of the end of the year had unfolded and her boyfriend of 14 years had killed the greatest wizard of the age and ran off.
All in all a very interesting piece. I look forward to discovering who you are at the reveals!