The 35 Whelen would be good for all nondangerous plains game. In most places, shots won't be over 200 yards.
The 35 Whelen would not be legal for elephant, rhino and cape buffalo. I don't think it's legal for lion anywhere and I'd want to use something bigger anyway. It would be fine for leopard but you would have to check on the legalities of using it since some areas may require a bigger cartridge.