It's a bit too much of a change (don't jump the shark), IMHO. In HY, we see a woman, who vaguely resembles Kahvi and later wanders off with his siblings. Apparently she was more of a stepmother. His father (stepfather?), from whom he inherits his animal-manipulating abilities, starves to death for him... This man obviously can't be Winkin. So, if the new theory was true, Kahvi and Windkin recognised* (Tyldak still alive, because the two parted after his death), for some reason she didn't really care for the child and left (presumably with Windkin and Tyldak, who never gets a mention). Teir was then raised by step-partents (only to be lafter left from his new mother, again), in a tribe, where at least some people have the same (up to HY unheared) magic ability, even though they do not share a bloodline. Oh, and when Windkin retells of his time with Kahvi and Tyldak, he forgets to mention, that he had a/some kids with Kahvi. Or that they ran into some new tribes. *Though, didn't Teir somehwere say his parents haven't recognise?