Nah, it was definitely a grizzly. It's entire existence is a reference to a movie called "grizzly. Apparently fox and the hound movie had a troubled production history, including one of the animatiors supposedly going insane and biting people or something, so I'm more willing to chalk it up to a mistake, or different people had a different idea on the setting or something. And as you said it looks like a black bear, so they probably weren't too concerned about wildlife accuracy in the first place. Not like that's new, In mulan 2 there are skunks in china, that doesn't suddenly make it take place in the americas. I guess you could also say it just walked there from its natural range, that's not new either and the original maker of the map did say it had an Appalachian feel to it.
On your description, asking about 'Anastasia' and the other movies, Disney now owns 'Anastasia'. (They also owns Fox.)
Here are links that explains a lot about Disney owning Fox, especially 'Anastasia'