> I'm wondering how all of that is going to affect modern navigation and what effect it's going to have on GPS navigation, as well as magnetic compasses

I hadn't considered that far yet! What an interesting question. As well as the rest; if I ever write further in this 'verse I am definitely going to revisit your comment to remind me what not to forget to address!

I was definitely already thinking Aulë's Children --> Furlings/Asgard, in some fashion. Not so much the Nox, though; the twigs in their hair made me think more of Treebeard's people, if they ever found the Entwives and evolved into a slightly more quickblooded species. =)