I'll probably have the chance to try out a Sleeper with bow of war this weekend: Looking foward to it!
For the thug, I had some underwater fighting to do so I geared up a Sea Troll King. It worked. My god did it work. A huge thank you for all the recommendations everyone
I didn't have the chance to try out Earthquake yet (2 Earth is the best late age T'ien Ch'i gets so it takes some effort to cast a 4 earth spell in battle) but I'll be sure to do so before the game is over for learning sake.
I have a new question and for once it's super straightfoward:
What happens if your capital is under siege and you have an Immortal unit that die? Do they:
a) Die and never respawn
b) Respawn and immediately attack the enemy that is sieging the castle
C) Respawn inside the castle with the other defenders