This fic is epic win! The GWTW borrowings are a delightful way to illuminate and sharpen the HP characters. To me, it seems that of all people, it's Tonks who comes through as the only one with any genuine understanding of others. Harry, Remus and of course Snape are all as self-deceived as they can be, and for some reason none of the Weasleys, not Hermione, not even Minerva, have any clue either. Poppy does, I think, but then she's not around any more after Lily Eileen's birth. So that leaves only Tonks as a person who not only works at being kind, but sees others for who they are as well!
Which made me cry all the more at Tonks' death. A very affecting scene! And all the relationship-hostilities mixed in with it were even more angry and angsty by comparison.
Funny how Harry started out loving a completely wrong image of Snape (ROFL at your deflating the "Snape, The Renaissance Man" cliche!), then when he couldn't make Snape respond, he switched to mistreating him but again, based on a completely wrong understanding. I was really getting so worried for Snape's happiness - unlike GWTW, I actually *do* like Snape, whereas Scarlett is just an amusing, appalling, egocentric idiot. I wasn't sure I wanted to finish the story! But I did, and the last line IS TOTAL WIN. Thank you for not succumbing to the temptation to have Harry retaliate completely! And for not having Scarlett!Snape miscarry, or little Lily Eileen die, which would have totally broken our hearts :-)
Well, that's two fabulous Snape/GWTW crossovers, one Snupin and one Snarry; the first one comedic and this one deeply engaging with the tragedies of ill-timed and unrequited loves. I can't think how much more lucky we can get! I was almost afraid to read the ending. But your last line is TOTAL WIN. ♥ ♥ ♥
Also, I agree with many other commenters that your depiction of the many mixed feelings was masterful. I like the way Snape's interaction with Lily shows so much about him, though none seem to read and learn, except Snape himself, and OMG he sure left it till nearly too late! I like the complexity that his nervousness around Lily shows, how Snape substitutes possession and power for love, because he fears that love will be like giving birth to her: giving everything, and having others take it away, leaving him with nothing to hold on to.
I also loved the scene with Remus where they forgave each other, and Snape's wry humor about not being able to take back his death-bed forgiveness of Sirius when instead, he survived. Most of all, that scene is awesome for their loving but no-longer-erotic hug, which you describe so beautifully! And which tragically, even maliciously, everyone else misinterprets. There were definitely points in this story when I wanted to scream and bang some heads together to knock some sense into everyone!
WHEW. SO GLAD IT TURNED OUT SO WELL! What a total, deliciously written win. I'll enjoy rereading this again for all its many levels of meaning, and the great writing.