Wow. What a fabulous, complex and intriguing plot. I was sucked in and held captive until I could finish it. Now, I want to go back and reread it much more slowly, savoring all the little details.
You do a magnificent Snape. He is very believable and so finely drawn. Harry is lovely, too. I love to see him older and more careworn. I also love your portrayals of the other characters. You made Tobias human. Well done.
I'm usually pants at guessing who wrote what, but there aren't that many people who could pull this off with this kind of skill. I bet I know. *g*