Great story, great premise, great characterization. I love your Rita voice; she is spot-on in all her incarnations, from brittle, ruthless reporter to "Edie." You play with the themes of transfiguration/transformation/magic and memory in all sorts of interesting ways, and your writing is top-notch, full of revealing detail and perfect diction and hilariously apt moments. The pairing is inspired. There isn't a lot of Marge fic out there, but I always enjoy reading it, especially when you've created such a multi-layered version of her. As others have said, you manage to make both characters into people we can care about while keeping their less-attractive qualities intact. I find myself rooting for Marge and Rita/Edie to make a go of it.
And I even get a chance to use my Aunt Marge icon!