Guns and ammo don't grow on trees; and whoever the supplier is will want something from the end user. Nobody gives away weapons for free.
The same as the British did I expect. He'd just have a much larger pool of entities to deal with. Note that getting guns wasn't a insurmountable problem in OTL, with less suppliers and less leverage.
Given that nothing + nothing pretty much ends up as nothing, what exactly do the various tribal societies - none of which have much - have to offer except the bodies of their young men? Who, after all, are not particularly numerous, in comparision to the shiploads of Europeans walking down the gangplanks in various Atlantic ports?
I think you are confusing the strategic problem with the tactical one. In other words, the long-term problem of immigration to the US with the immediate one of the number of men available in
this war.
However, it is pretty irrelevant. A Tecumseth vs. the US fight with no Canada or Britain in the mix can have only one outcome. Even if he'd gotten all the tribes to join his confederacy, he'd have had a population base of about 100 000 vs the US seven million.
Again, the native societies didn't exactly thrive in South America, which was about as balkanized as any conceivable North America (even including New England, New France, New Spain, New Netherlands, etc. and all their possible daughter colonies) could be...
They didn't do real well in Australia, Tasmania, and New Zealand, for that matter.
Actually, they didn't do that badly in New Zealand. Or Hawaii, Ethiopia, Japan, New Guinea, Tibet, etc. Every setup is different.
Well, it was good enough to get Tecumseh killed, who was pretty much it as far as early Nineteenth Century "local" empire builders for the British or whoever.
I don't really see the point here? Washington had two horses shot from under him. Davy Crockett died at the Alamo. It happened back when leaders fought in battles.
I think you are over-emphasiing the ability of Tecumseh or any Native leader to do this, given the fact that all of the sucessor states of the failed USA will be expansionist settler nations, aimed not at trade advantages with quasi-independent native chiefdoms, but at taking and living on their land.
I don't see how that is possible, given that 8-9 of the states seem to have land borders with other states or British land.
The point I am trying to make is that Tecumseth OTL was never going to win. But he still did far better than you'd expect under his circumstances. If the United States balkanizes as he is assembling his coalition, his circumstances change. A lot.
OTL he worked with the Canadians and the British. If he had the strategic vision to play the balkanized US nations against each other (There would have to be some bad blood there, 18th century nations didn't do velvet divorces much) he could go quite far. Not the least because he could present himself as the least threatening option, a potential ally and the tiebreaker.