Tricky subject i guess, you could take some of the flint worthy weapons and ideas from Kobold Camp as a basis to gamestyle.
I sort of cheat elves into easily accessible obsidian, handwaved off with 'Its Magic' traded for logs for wood tech level without metal, so i can forsee something similar for your primitive civ's efforts (also works for obsidian picks)
But i suppose you could go the way of Kobold camp with a salvage/knappers pit in order to give you some basic equipment that the carpenters can't, else without exceptionally sharpening wood with a forced edge (say if the knapper simply sharpened spears instead of crafted a entire solid stone obsidian one or craftdwarf a generic obsidian sword) though you could make a entirely seperate foriegn weapon with a 'Tribal' adjective that wont appear in sieges like the enclosed example.
Your tribe would have to live in caves probably, (if you have the advanced map setting on also, they shouldnt be invisible, [SKULKING] conceals map populations on 'c' screen but you need visible caves to actually see civs highlighted in the holdings & occupation legend) as to keep them off a pernament civilized settlement because there aren't any camps.
Sorry if this has been more of a technical feedback input than a creative one, I look forward to what you produce.
I disagree with FantisticDorf on a few points, first and foremost that I don't know of any native american tribes who lived in caves.
I am Chickasaw, so I will relate to you my specific tribal knowledge - there are so many tribes and each one is unique, so a blend of styles and tropes is most likely to be what you end up with.
Many Plains tribes are nomadic, which means that they hunt bison, following their herd as they travel and migrate around, making no permanent homes, and using teepees and wigwams as shelters. I'm not familiar with a DF civilization type that can emulate this easily.
My people are known are part of a group known as southeastern mounds builders. We built mounds on top of which our cities were located. Typically most families had two simple one-room homes - a round hut that we lived in during the winters, and a square lodge that we lived i during the summers. I think that the closest DF can get to this are forest retreats, and your best bet for a race are elves.
We played a game called stick-ball that the french took and made into Lacrosse. The difference in the native american sport is that we referred to it as "the little brother of war" and we tried to resolve conflicts with neighboring tribes using a game of this. The rules were to use two sticks with small nets on the end to throw a small leather ball at a goal post, one on either end of the field. Any additional rules needed to be agreed upon before the individual game. A lot of times, one or more people would die during the game, because it is so brutal. In addition to the wartime games, we have a yearly game against our cousins, the Choctaw tribe. This yearly game continues to this day.
Might be worth pointing out that America has no native horse species. They were brought by the europeans, so depending on your period-preference, you may or may not want to include them. And while we did keep some herd animals and milk them, we did not make cheese or alcohol. Tobacco was used by tribal medicine men or Minko.
Our political leaders were elected officials known as Minko. The closest translation is governor.
FantasticDorf is spot-on with the obsidian weapons, I think. Spears, Daggers, and Axes would be the primary weapons of choice.
I think that if you are doing multiple tribes, you should probably make like two or three and be comfortable with them each being portmanteaus of several different tribes, rather than trying to simulate several specific real-world tribes.
It's probably worth pointing out that Native Americans (as in people native to North/Central/South America) did practice Metallurgy to various degrees, mainly in south and central America.Well, nomadic stuff can't exactly happen in DF... so...
https://en.wikipedia.org/wiki/Metallurgy_in_pre-Columbian_America
https://en.wikipedia.org/wiki/Metallurgy_in_pre-Columbian_Mesoamerica
For what it's worth I think it would be cool to incorporate more nomadic civ behaviors, I'd like that for Beast People.
Definitely not an authority, but I spent a lot of time with the Oneida - a branch of the Iroquois confederacy.
I would recommend looking at farming and trying to expand/specialize in that. Perhaps growing plenty and expensive crops would be the main resource for a First Nations game. I'm sure you've heard of Three Sisters farming - being able to pull three crops from one square would be invaluable (I have no idea if that's possible.)
Additional crafting resources like using corn husks would be in keeping with reality.
Values like family and music also make sense.
Pedantry here but horses are native to North America, along with camels... they just kinda died off before humans got there....
Might be worth pointing out that America has no native horse species.