Resolved: to ignore pesky historical problems and write the story.
This does not mean I plan on ignoring history, or even those problems I've just resolved to ignore. It means I'm not going to waste time finding the answers when I can easily gloss over them. The sticking points aren't that important, and adding in another character isn't that hard and won't change the story significantly.
I'll go with what I know inheritance laws were for most of the world at that time, and be done with it. If I need something specific, I plan on looking it up afterwards. This might not work, those things have a habit of coming back at you, but c'est la vie. If I don't stress now, some of this story might actually be written.