The thing about bears is that in North America they are basically two types of species. Not in terms of blacks and browns and Kodiaks etc. But rather the garbage raiding bears of the east coast who have found their niche among humans. Which is not to say they should be treated as tame animals because they are anything but.
And then there is the other sort who live in the West and the North and still think of themselves as the great predator of North America. Yes I know Polar Bears have an annual garbage run, but they do it because they seem to think it is their right. And if they are hungry they have no problem with seeing you as a food source.
As it happens I am reading a steampunk novel named Vermilion. As a side issue the North almost lost the Civil War, but Lincoln signed a treaty with the united bear tribes. Who are sentient and speak English. As can Sea Lions.
Now the thing about alternate histories is that they are really no different than regular fiction. All fiction has alternative worlds. Regular fiction might even be more so. As an example, Caleb Carr has written several mysteries set in late 19th CE New Your City, and which often include historical characters. We know the Police Commish will become President of the United States . He is,btw, Theodore Roosevelt. But in normal fiction, be it real or genre, we know neither the past or future of these characters. Only each moment that the writer gives us . But what if we are the writer. Do we reveal the world to the character or the character to the world? Or do the characters reveal themselves to us first.