So, today was spent getting the hang of Kompozer--you can do a lot with it, but my God, it is not an intuitive piece of software.
I had to use Kompozer because it's an HTML editor, and Amazon has actually gone backwards in terms of what you can do with your e-book without getting into the HTML. As I mentioned, chapter ornaments are suddenly this HUGE problem, and other things are harder to do, too--it's really annoying that they've actually managed to make it harder to create a decent-looking book, because it seems like with Kindle Create, you're going to have so many nice interiors now.
Anyway, I think I'm 99% of the way there.
ETA: I do think I'm going to sacrifice the chapter ornaments for Trang and Trust and reformat them through Kindle Create one of these days. I kind of want to update them anyway, because there's stuff like the links in the back that don't work any more.