Each of the four themes can be extrapolated from the relationship between T’Gatoi, the Tlic and Lien the terran and her family. The one I felt the most in this story though, especially toward the end when we figure out about N’Tlic and T’Khotgif was manipulation.
From the very beginning with the eggs, all the way until the end of the gruesome hatching, the terrans were used as cocoons and eventually food for the offspring with I’m not really sure what tradeoff. They are taken care of and protected I suppose from the outsiders but with this fate at hand, like that of Lomas they are kind of doomed sooner or later. The span of control does not end with even the conversation between T’Gatoi and Gan at the very end of the story where the Tlic explains her plans on who will get T’Khotgif, but her family business and profession is politics! Not only does this creature have the control over this family in the home, but even has a say on the laws that get passed in their society. I would say sure they are enslaved in a sense. There is a clear hierarchy in the world they live in. There is surely a symbiosis between the two but the fact that they are essentially drugged constantly throughout all of this from the egg goo, makes it seem like there is less of a choice and that it is just easier to make them subservient to the reality of their relationship in this way.
I agree that manipulation was mostly the main component of the story because of how easily swayed the humans seem to be.