A Pokemon that can handle Water, Flying, Ice, Fire, Ground, Grass (Situational), Rock (Situational), can stop/revenge Moxie/DD Gyarados and break through Heatran? That doesn't exist in one Pokemon.
And you should remove Arcanine. It doesn't do anything for the team, and just compounds weaknesses. Donphan would be okay for priority Ice Shard, a physical pivot, and rapid spin, which would be a saving grave for this team so that Ninetales would have a better shot at winning weather wars and Volcarona isn't neutered when it switches in.