okay wait I just thought of something else that may refute our agreement--
Tobias.
Tobias is totally a human, right? Except when Elfangor landed, he automatically had a connection to him. And when Ax was "mirrorwaving" or w/e, only Cassie and Tobias heard him. Cassie, b/c she's just *in tune with nature* or whatever, but Tobias...because he is part Andalite? And then there is that whole utzum thing from book #33. How could Tobias get a message from his ancestors if he's not even the same species as them?
I mean, all of these things were explained away with different in-story wank--he could hear Ax from beneath the ocean because he was in morph, and "mirrorwaving" only works with users of Andalite technology, and the utzum thing was apparently explained because Tobias had morphed Ax and had Andalite DNA in his bloodstream, but idk. I always got the impression that Tobias was part-Andalite, even though he wasn't born that way, only because his father was an Andalite-turned-human nothlit.