This is a fantastic review! I love re-reading it. Thank you so much. 'Flawless'? Wow!
That's a brilliant way of understanding Snape: as someone infantilised by his need for a father figure. That's a very good way of explaining how I was trying to write his position in DH, and therefore in this fic. He's an apprentice who has been left alone by his master who has also charged him with a difficult and dreadful task to complete on his own.
I also agree with your assesment of Aberforth. He's a humanitarian on a small scale, looking out for individuals, with little sympathy for his brother's larger scale. I'm also glad that you enjoyed the way Albus seems to be in the fic, although he's dead.