The terminators: Incredibly useful on 7vs8 attacks (similar to 8v8) so the full 8 scenario on hardcore is probably the best scenario to use them.
The natives: In full map mode, it's most likely the best race at the beginning of the game, since there are plenty of 1's laying around.
The undead: Terrific, since you can use double attacks on 8v7 and so on to avoid super unluck and still have plenty in reserve.
I'd say these are the most interesting races of all that were introduced to the game

Great job Lopdo!