The way you've seamlessly woven your every element together into a coherent, familiar yet refreshing whole leaves me in awe. It's a real pleasure to recognize the HP characters without ever doubting or tripping over their AR incarnations, and I'm astounded by the power of your storytelling.
The moment that resonates the most with me is when the church throws Severus out before he leaves for the castle with Sanguini and the others; it made me sob. And I thank you for your handling of faith in this story—not just because Severus is a man of faith, even though one in crisis, here.
Also, I didn't so much read this story as watch it play in my mind like a movie; your prose is marvelously vivid without being over-blown, something that is difficult to accomplish, I think, particularly when crafting scenes of such enormous emotional impact. I was moved, reading Exegesis, and satisfied by the domestic happiness Severus and Harry find together by the end of your tale. How you could make any ending not seem anticlimactic, or lose your pacing, after the scenes in the monastery is beyond me, but you managed it with grace.
My only quibble is that, while I accept Severus and Harry's relationship without question and do see reasons for their connection stemming from the story as you've presented it, I don't know that I would have accepted it so completely had I not already been a Snarry fan; it seems not forced but a bit rushed. Honesty compels me to admit that, even though the rapidity of the bond between the two in no way diminishes my appreciation or enjoyment of your achievement, which is now firmly rooted in my mind as one of the finest stories I've ever read.
Congratulations, Femme. What you've created is brilliant, and, even though I know that you must have down an incredible amount of research for this story, it flows beautifully without being weighed down by it. I was utterly absorbed by your tale. I can hear the characters speaking. I can see them living their lives. It all feels real and right, and it was a privilege to read something so amazingly well-crafted and beautiful.