If a Native American setting is being planned, I suggest an Inca or Aztec setting.
Quetzalcoatl should make an appearance. Stamina potions should be made from chocolatl
.
As for the Norse setting, I hope to see the most famous elements of the mythology expressed, including the cosmology, Yggdrasil the World Tree, etc. In QFG3 you had different races, like the Leopardmen, those Liontaurs, and the human Masai-like people, I forget what they were called. In the Norse setting I think there should be a Frost Giant lair or stronghold, and a Dwarven city. Dwarves should really be involved, since they're mostly of Nordic inspiration, I think. If anything, the blacksmith should be a dwarf, and the Hero should be able to eventually by some cool weapons and armor from him.