Of course, these are things I didn't have in mind when I wrote the first couple of books. So once the draft of Book 5 is done, the plan is to revise the entire series as a single unit, as though it was all one book, to go back and make sure all those different bits of story are the way they should be early on. That's an advantage of writing the whole series before you start to revise or release any of it; you can let the story develop how it wants to and then after you get to the end you can go back and make the earlier parts match up with the later parts, why certain things happened, what's going on in the background, and things that turned out to be important that you didn't think were all that important at the time. I'll go back to the beginning and bring it all together so the whole series is solid and consistent and hangs together.
Now that I'm planning Book 5 and have a pretty good idea of what actually happens in it, I've written quick blurbs or teasers for every book in the series, so you, my readers, can get an idea of what's in store. For now, it's on the Still to Come page, but I hope to soon be able to get Daughter of the Wildings set up on its own book page.
Added: Daughter of the Wildings now has its own page!