Hee, you know much as I loved the fic (which I did, in spades) the thing that cracked me up the most was the end notes.
I was convinced for half of the fic that Snape was Harry's rival, especially when I initially found out about Harry leaving. Umbridge was much more amusing though, I never would have guessed.
Hee Snape taking out a contract on himself, and numbering/lettering issues and Fred/George/Angelina (for that I love you very much).