For the first one, guard any time the wolf "opens its jaws". Wear both wolves down gradually and don't kill one unless you can kill the other in the same turn. They get more powerful when their partner dies.
The second one, guard your lowest hp on turns 6, 11 and 21. Don't use Morvay. The sprites can't be killed, only worn down to 25% hp. When they're both down to that level you'll win.
The third one is just an endurance test. Just use your highest HP and keep attacking Quincy, don't bother with Kuya. Quincy will heal three times but just keep attacking and you'll win.