Mature? *beams* Why, thank you! I'm rather amazed myself that I pulled it off without too many loose ends left flapping in the breeze.
As far as I'm concerned, Albus owes Severus big time. He left him in the dark about the whole Elder Wand business, thereby condemning him to die at Voldemort's hands. Even if Severus had survived the war's end, the fact that he'd killed the great Albus Dumbledore would doubtless have sealed his fate in the wizarding world. So whatever else one thinks of Albus, most of us would probably agree that he was an unparalleled manipulator of the people closest to him, Snape and Harry in particular. Depending on my mood, I can believe that he was more or less benign in his meddling or I can see him as considerably darker than I portrayed him here. One thing, though: he was far less emotionally honest than Severus, who may have been able to deceive a Dark Lord but who scorned in general to hide his feelings. Despite Albus's machinations, I don't think he was actually expecting to relinquish Severus so completely. It's hard for a puppet-master to cut his puppets loose from their strings and let them walk free. (Oops, there you go - that's what I mean about seeing him in a more cynical light.) Lily's more aware and mature when it comes to understanding what she's giving up - at understanding that she must, in order for Severus (and Harry) to have a chance.
As for Sirius, heh. I wouldn't worry. I fully expect him to figure out how to get what he wants, in which case Tonks might be forced to wake up and smell the Regulus notice that there's another, younger member of the Black family hanging around. Not to mention that Remus is a waffler from way back and unlikely to put up much of a moral struggle to Sirius's claims on his, uh, person. ;)
Thank you so much for this delightful comment. Someday I hope to write a fic about Albus and Severus, because there are just too many complex and unresolved threads tangled up between them to resist. For now, though, I'm glad you enjoyed the way this particular tangle worked out.