John, I think your intuition may bear out to be true. I found the tipi model in several places, shared by Indigenous writers, about the Blackfeet. But based on feedback like this and from other readers, I am doing further research. Professor Cindy Blackstock, Gitxsan First Nation member, and University of Alberta Professor, shares as described here (https://lincolnmichel.wordpress.com/2014/04/19/maslows-hierarchy-connected-to-blackfoot-beliefs/) the tipi model. She also writes beautifully about the "Breath of Life" theory here (https://jswve.org/download/2011-1/spr11-blackstock-Emergence-breath-of-life-theory.pdf), and includes several circular representations as well (though these are not linked to the Blackfeet at least in this paper, but could be more accurate portrayals).

I'm working on some additions / revisions based on deeper contact with closer to primary sources, if I can get them (with proper acknowledgment if I do wind up getting any of this wrong myself). Thank you for your honest feedback!