yes great white sharks cannot be kept in captivity. but this is a game. If you say it wouldn't be realistic, I'll tell you something to be not realistic about the game, animals don't attack people, it's not realistic this.Considering Frontiers' approach regarding enclosure requirements I guess you can pretty much skip any of the mentioned big whale species.
Blue, Grey, Humpback, Sperm or Minkwhale would probably be "Planet One basin per zoo".
Moreover Great White Sharks obviously cannot be held in captivity as all attempts doing so ended within three weeks with the death of the animal and also there is only a handful of Aquariums worldwide which have Whalesharks in their basin.
So except the seals, turtles and manatees I think your list will remain wishful thinking.