Glad you enjoyed it, Paradox. I must admit that Trail of the Huntress was my favourite storyline of the series as well. When I wrote The Chosen One, I did what I knew was expected, so there were no really big surprises. The only major surprise for me was how Femke's character evolved through the book to a point where I really wanted to write more about her - hence Imperial Spy and beyond.
The series was always planned as four books because someone once told me that a publisher would expect to lose money on a first book, break even on the second and make on the third - I planned four just to be on the safe side!
I do have vague plans for a follow on trilogy set 3 years on with all the same characters, but it's going to be on hold for several years now, I feel.