I don't know about Adonalasium and evolution, but I always saw the LIsteners as the natural progression of Rosharan evolution. The carapace armor being a throw-back to the carapace shells of the greatshells, white spines, etc. It's the humans, who HAD to have developed off world since they have no protection against the highstorms, and the Ryshadium and 'normal' Horses (Am I the only one that thinks that the Ryshadium are horses with Spren?) were brought with them.
It raises the interesting point that the 'heroes' of the story are the invaders (normal humans), and the Indigenous people (the listeners) are the 'bad guys'. Maybe we've got the story all wrong and have been rooting for the Cortez's and Pizarro's all along!