Zen Daijun - I took the path that -wasn't- the cave. I felt like exploring and went around into the back entrance of the caves. The Miasma clouds don't cause the Enviroment Effect.
Haijun Lagoon - Not sure about the quest name, but it's the one where you first meet Su, Gai, Kai Ying and Tai. Two of each character spawns, and the quest is a breeze.