I'm not sure I can be more coherent even now that I've had some time to let the story settle in my mind, but I'll try.
This was a great remaking of the wizarding world. I loved your OC (for a while I thought SHE was Snape) and when she ended up with Ginny I LMAO! Poor Ron... And Hermione was lovely. Poor Molly. It took me a while to understand what was happening to Harry and then in the end when Snape took the ghosts from him... *sobs*
*sigh* You see? Still incoherent. I give up. I loved it. I'll just stop there.