Most of them actually fit nicely, so it is not a big problem:
NPC Cities that trade with Nations on the northern trade route
- Northcove: Horses (Military Animal). Could be used as Livestock, so not too far
- Willowvale: Rubies (Gemstones). This is a bit trickier, but points to a mining regions, which is what I have :D Rubies can pop up in the capital as part of the trade
- Foundation: Post-Traditional Sculptures (Art) actually matches!
Let me know if this is fine :D