The diversity in Bonebonded comes from the different characters' aspects and how different the giants are. I also recommend making new stunts because that's a really effective way to differentiate characters thematically and mechanically.
Since I have you here where is the ocean and Viking long ships and raiding and stuff? Can I add that? Is that just the wrong culture? Or maybe if they had access to oceans they'd just leave and not be beset by giants?