Interesting strategies. For K'tahu on my impossible mage with no loss battles I found that paladins moved too slow, and that the trex fear would make me lose. So what I did was I used....
repair droids
Yep. Just one stack of repair droids. Stoneskin, Divine Armor, and phantom. It took about 30 turns I believe to kill him. Hellbreath worked nice too, to up dmg. And I used calm rage alot to get mana back.
For Baal, the paladins extra damage to demons and phantom res was essential. Droids couldn't handle it.