I think whatever you choose will be great. And I'm not really qualified either.
The only thing that makes me a little nervous is the bear thing. I'm not sure I'd want to trust either of those. I might be wanting to tote a .30-30 in that case. Or a Socom might not be too bad. I think it easier to pack than a Garandand I think the recoil impulse isn't too bad.
If your AR was a 1/7, the 75 grain TAP ammo might be a good choice. Or, some Trophy Bonded Bear Claw.
I don't envy your position as to which one to take. But I think if you trust the carbine to work, it will work. I also think that usually things go TU in the most inopportune time. I have always been a little leary of autoloaders of any kind for this reason and find myself thinking a bolt action, lever gun, or double barrel would be the most dead nuts reliable. But obviously follow up shots are in issue with those in comparison to an autoloader.
One more thought. A 4"-6" .357????????? But then again, is the carbine that much more underpowered than one of those? Or the AR? I would imagine not, but I know some people swear by .357. If you have shoulder issues, maybe that might not be a bad idea though. Or a .44 or .45 LC.
Anyways..... You'll make it work. Anything you take, you'll make it work.