Yaone's actually introduced fairly early but she doesn't get as much screentime as the male characters do, unfortunately, so it's fairly easily to miss her in the shuffle there. I could see Yaone being interested in her perspective on life and death as such a long-lived person, too. Philosophical discussion could be a fun thing.

(You're welcome! Haha, I haven't submitted anything for publication myself yet but congrats! Writing fiction from scratch really is a long process for sure. So much world and character building, plotting, and then there's the actual writing and rewriting...)