I really hope that this posts because IJ has been wonky all night...
It took me a while to understand what was happening in the story, you really built the plot slowly and carefully, layering the facts until I finally got the full picture. It was quite suspenseful right up to the very end when I was literally on the edge of my chair, nervous to see how it would all turn out. Very effective technique! I enjoyed Binns, and the castle, and even the tiny cameos from Hermione and Ron. It all made perfect sense once I understood why it was all happening. Well done! And Severus as a Phoenix definitely made sense to me. ;)