Wow, I really like this!! From beginning to end, it had me captivated. Remus at eleven saying he's no longer a little kid when he still should be )): Sirius pretending to be Severus is the funniest ever!! I love this:

"Sirius peers into the amber liquid, unable to stop the smile tugging at the edges of his mouth. 'Ah, Prongs, s'worse than I feared.' He looks up, widening his eyes. 'You will-- you will never shag Evans. Sorry, mate.'

'Don't have to be a seer to know that,' Peter mutters blearily around the rim of his glass, and James boxes his ear."

Aww, Peter! I adore your characterization of these boys. A really lovely piece of work!! :D