As it sounds like all the storylines by other authors (or anything in them) are now potentially non-canon, it's possible that a few of these things will change. It does look like Tier is Kahvi's son, but his father might still have been a cool and unrelated plains elf. I'm kind of looking at all the other stories as though they were told and retold so many times that the details changed (or else I'd just get annoyed at the revisionism, I guess). That's how I looked at the Worldpool and BoTC stories, back then, because of the inconsistencies. Was it ever stated in a Pini-written story that Kahvi is Two-Spear's daughter? Because that might not be the case. It'd be weird to change that now, since there was that entire miniseries, but that was a long time ago, and there were some inconsistencies and other issues with it. There are also other, surprisingly significant details from other stories, that were also changed/edited out for Final Quest, and actually farther back, beginning maybe with Searcher and the Sword and Discovery.