Thank you. I appreciate your thoughtful and detailed comments!
but you left it graceful and spare
Hemingway's Iceberg Principle, FTW. ;-) Half of my writing is trimming, I swear.
I don't have to be a Miz fan to follow the references and appreciate their use
That was the idea: to convey what the song meant to Harry and to Severus, rather than requiring the reader to know the song in order to understand what it meant to them. It's enriching if you do happen to be familiar (the song is "Bring Him Home," sung by Valjean--you can hear it on the official Les Mis web site) but not essential.