What a charming, tender story, Mystery Author, and the illustrations were wonderful. I especially love Augusta's hat - she seems to have kept her taste for feathers as she aged; too bad she didn't keep the lovely flowers, too. :-)
When I saw that you'd made her a Rookwood, I wondered if she was Augustus' twin. Augusta/Augustus seemed like the sort of thing a pureblood family would do. It's fun to think of her as a young woman, tall and feeling awkward and looking toward a powerful elder for guidance and maybe a bit more. She seems as forthright and determined even at this young age as she does as Neville's gran. It's shame the magical world is even more hidebound than the Muggle one.
Madam Marchbanks, for her part, is just as delightful. I love her refusal to give in to temptation while Augusta is a student. I hope she is amply rewarded for her rectitude later! Lovely job, Mystery Author!