Very interesting article. I have thought of posting a thread about the bigger point of divergence of horses surviving in the Americas but have not done so.
Really interesting, and gives a nice perspective on the precolumbian Americas, as well as just the diffuse impacts of these kind of single interventions at very long timescales.
I wonder how far north the Appalachian llamas could spread, and what difference that would make for the tribes living in what would become Canada OTL. I'm also curious about the impact on the tribes living in the Pacific Northwest.
All in all, this TL could have as much potential as @Jared's Lands of Red and Gold, one of my all-time favorites for the originality of its premise and setting.