Lol, aside from Lupin's father inpregnating some woman and then running off, leaving her with Peter/Remus twins, you brought up a good point about Peter's hand and the downfall of Lupin.
Silver, like the moon, is fatal to warewolves (I don't remeber where I read this, but it is true.) There's a reason that JK made peter's hand silver and not another colour. I think that the death of Lupin by Peter's hand is a defnite possibility. Well, not the hand itself, but in the metaphoric sense.