This is an absolutely wonderful story. Let's take as a given that I'm pleased about Snape's survival (becuase...of course I am *g*), but he did it (you did it) in such a clever way - giving him an entirely new life in an entirely believable way.
And Horace is wonderful as well. A perfect voice, utterly Slytherin, not a bumbling fool (honestly, I can't understand why so many people assume he's an idiot), and - amazingly - willing to give up all the networking possibilities at the party in order to spend real time with Benjamin-who-might-be-Severus.