Usually, wolves will get along with other wolves, (like packs) but if a wolf wants leadership or a lone wolf comes near, they will usually attack another wolf.
By scent. Each wolf has a different scent. Rarely a wolf can tell a pack member by a characteristic they have or how they act within the pack. But mostly by their scent.
Yes it is a subspecies of wolf though it shows many fox-like characteristics it is not closely related to foxes and lacks the elliptical pupils found in vulpine caninds.