Which coastal federation?This sounds about right. I like the coastal federation. What's their culture like? Buddhist? Tribal religion?
I'd think that the "indigenous" groups would, in terms of descent, have a strong "Mercan" background as well, but still be basically indigenous. Culturally, do they have any influence from Merca?
Do you know anything about the Yukon? Geographically it sort of forms a piece with Alaska.
The Great Tribe of the Aleuts have a syncreticism of indigenous beliefs and a bit of Shinto and Buddhism picked up from traders (I plan, if we ever get to the Old World, to have a large Japanese cultured state in Siberia, and they'll also being in contact with the Buddhism PNW). The Confederation of the Yupik have something similar, but there are also some Christian beliefs in there as well (although fewer Buddhist beliefs since they don't trade with the Pacific NW). The tribal nations to the north are mostly indigenous, although there are still a few traces of Christianity.
As for the Laskan Federation - its odd. They've kept their Christian faith, and put up with the Buddhist traders from the PNW because they need their goods. They have picked up a few extra saints and tales from natives, but more importantly they've also undergone what can only be described as parallel evolution with the Norse beliefs of our history.
The Devil is now seen as a figure of cold and ending who dwells at the top of the world (this also makes peoples like the Inuit and the northern tribes, who live off the ice, seem like demons) whereas God is a figure of warmth, a god of hearth and fire, with the Sun seen as God's Lantern (give them a few more centuries and they might start worshipping the Sun as God, and then they'll basically follow R'hllor from ASOIAF), which provides both warmth and the light to make plants grow (even though fishing provides a lot of their food, agriculture is seen as want differentiates them from the Northern savages)
They envisage the end of the world will involve years long winters, where they will be able to survive because of their dedication, holiness and knowledge of such - during this time, some will either die from being unprepared (the southerners) or turn to the demons to learn how to live on the ice. Eventually, though, God will defeat the Devil forever and the entire world will be made a warm paradise for them to resettle (this is quite possibly a really old cultural memory of global warming )
The indigenous groups do have a bit of a Mercan background but they're still predominantly indigenous. The Americans didn't fare well in the few large towns north of the Alaskan Range, and the result was those that did survive absically had to turn to the tribes (if the tribes, struggling to recover their old ways, would help them) to survive.
As far as the Yukon, I hadn't really thought about it, but it is a problem. The Mercans are safe behind the Alaska Range, and I think that thge geographical idea of 'Laska' will have expanded to include much of the Yukon, because the old boundaries don't mean much to the tribes there. The tribes in the Southeast of the Yukon might have contact with the northern PNW region by means of Lake WIlliston and the accompanying valley, but I don't know.