Zuko and Katara face Azula, Mai and Ty Lee in this scenario where the betrayal at the Boiling Rock didn't happen and where Mai and Ty Lee stayed loyal to Azula. Also Azula keeps her mind intact since the betrayal didn't happen.
The fight takes place at the Fire Nation Palace like in the finale but without Sozin's comet.
Scenario 2 : Same but during Comet Day.
Scenario 3 : the fight happens in a forrest near a stream during daylight like during the Chase episode.
Scenario 4 : in the Crystal Catacombs.