I've finished the series, but I'm left wondering about Moneta's transformation into a Shrike-like form during her last meeting with Kassad in the first book.
After that and during the second book before they meet again, Kassad is very unsure about everything regarding her. However, Kassad seems to have been put at ease again simply after they meet in the second book. The transformation isn't even brough up with her, if I remember correctly.
Almost all of the immediate questions left from the first book seem to be explained in the second. The others seem to be generally addressed at the end of the last book. But I don't think what was going on with that one meeting between Kassad and Moneta was ever discussed.