I think that when Jack comes back, he's going to have a hard time with the Denziens. In the time he has been away, they have befriended the Quinten Quads, learnt compassion for humans by soap opera and even developed sufficient sentience to engage in purely abstract art-forms like music! Evolved minds do not good minions/slaves make.
Now... I wonder how long it will be before the continual rythmic whistles will drive poor Kat insane (assuming she still has her super-hearing)?