IGJ: Prediction and QuestionWhorl

Prediction: On Blue's Waters was about both Horn's original time on Blue (getting to Pajarocu) and his adventures there after returning. In Green's Jungles was about both his original time on Green and his later adventures there through astral projection. Therefore, I'm guessing that Return To The Whorl will contain both past tense and present tense goings-on under the Long Sun, and that the title refers to the present-tense return that will not take place until the third volume, and not to his first return which he's mentioned in passing so far. My apologies for belaboring the obvious. Question: I never really understood the whole aquastor/eidolon thing back in BOTNS. Is it possible that Horn's (and others) physical manifestation during the "astral projection" episodes is an aquastor?