Let's see: you nailed your genre and your prompts. The use of Frost's poem to frame the story was well done. And I liked how you swung between the three time lines, bringing the reader along, so that we were all caught up by the end.
The thing I enjoyed most about your story was the plethora of original magic; the rituals of Albus and Severus, and Amycus and Alecto were all fascinating, and you had a rather unique story-line for the rise of a new Dark Lord. You have my undying devotion for making Lucius a style consultant. Hee.
Gus was adorable, and as kids either drive parents apart or bring them together, I was glad to see him accomplish the latter. Poor Snape, so misused by that old codger, but in the end, he's got his man, slightly the worse for wear due to the well-handled Mpreg.
Well done! I enjoyed my evening of reading, Dragon! ROAR!!!