Maybe! I was thinking closer to Inuit, but if you want to interpret them as Niddings, be my guest.

You did say you were going to throw in a reference to them, so of course I thought maybe this was it. :p

Eragon didn't see the truth about himself in his true name because it has nothing to do with his morality, only his fate

Interesting. I have to say I much prefer single word true names, because for one thing it's more practical and for another it gives you a lot more wriggle room when it comes to interpretation and such. Like if your true name meant "kingkiller" it could mean anything from you will be a hero who kills an evil king to you will be an evil traitor who murders a benevolent king, to you will become known for being really good at chess.