An excellent story; all three pairs hold together so well, and I love the way you offer new perspectives on fanon/canon tropes: it makes sense, for instance, that Molly and Arthur would have been ambivalent about joining the fight (love that shades-of-gray discussion with Gideon). I like that Minerva doesn't adore the Marauders, and I particularly love your picture of Arabella -- not the carpet-slippered caricature of canon, but sharp and able to hold her own with the magic folk, Squib or no Squib. (No surprise, probably, that Minerva/Arabella is my favorite of the pairings, but they all work well -- I think this is the first Augusta/Moody I've ever read, and I would love to see more of them. Really liked this bit: And here stood Alastor, certainly the worse for wear, but as alive and larger-than-life as he'd ever been. "It wasn't a mistake," she said, and his lips thinned and he gave a small nod. "I didn't say I had no regrets.")
I'm also impressed by the structure -- the bookends of Elias Mallet, told with such chilling, effective understatement. Overall, a great use of politics, canon, and just good storytelling.