I've hunted with mountain cur many times. Owned a few too. It is true they can hunt coon or squirrel and if you can keep them from running deer they can be excellent at both. Right now I have a squirrel dog BTW. It's a mountain feist. So far it will tree but won't bark at the tree. That's a common failing of feists. They hunt by sight and by winding which is great for hunting tree rats. But another big problem is he's gun shy. He'll chase bears off like crazy but bring out a rifle and he runs. He's getting better but he needs to get over it.
My dog looks nearly identical to the one at this site except mine has tan on his front legs.