It seems to me that a party of 4 lizardmen is hands-down the best party you can get: you lose a bit of damage you would get from headhunter, and your mage will have a bit less mana (not a big deal), but you are practically immune to elemental attacks, which are the most dangerous in the game since they affect all members of your party.
Even having just two lizardmen is pretty good, since you can then stack the relevant resistance items on the remaining two characters. But again, it seems to me that there really isn't a compelling reason to pick anything else but lizardmen, unless perhaps going with a single minotaur in the mix. This seems doubly true on hard.
Do you disagree?