Zahn will eventually need/want to explain how Thrawn came to work for the Empire
The first Thrawn book of the new canon handled Thrawn's "discovery" by the Empire and how he was folded into the system, but it's been a while since I read it and I can't remember if it delved into the whys and hows of him leaving the Chiss. I'm expecting that the last book in this trilogy will set it all up more neatly.

I'm a little flummoxed as to why Zahn added the Thrawn-meeting-Anakin bits to this book/trilogy, honestly, because I thought it had already been dealt with in the three previous Thrawn books and that these were going to be more focused on Chiss space than areas controlled by the Republic/Empire.


Thrawn's sister was a sky-walker!
I was also super intrigued by that! Or that at least Thrawn believes she was taken to be a sky-walker. He says that his parents refused to tell him where she went, and that he only made the sky-walker assumption when he was promoted to bridge-officer rank and learned about them. It's entirely possible that he'll turn out to be wrong-- it would certainly be a heck of a twist.