Had a thought while continuing to work on Book 3 -- even though I have been referring to it as a trilogy, and it is as far as the overall story arc goes, it's not really a trilogy, versus being the first three books in an ongoing series. I'd mentioned before how I had seven books in mind for the main series. That still holds true.
It's just that I realized while working that there were some characters and storylines that likely won't wrap up in Book 3. Rather than orphaning those elements, I'll just keep following them beyond Book 3.
Ideally, there'll be enough interest in the series that readers'll be up for those!