If you saw The Seige Of The North PT2, you saw Aang wasn't the one that really killed Admiral Zhao. It was that Ocean Spirit. Aang had been placed on that fallen iceberg or whatever and as the Ocean Spirit was retreating back to the holy spot where the new Moon Spirit was, it stopped long enough to grab Admiral Zhao and to pull him down into the water.
Now, how would have Overlord Ozai known about Iroh's being a traitor in saving the spirit and of Zuko's being at the battle? I think Admiral Zhao had survived to tell him. It's only a thought, but I think it's a good one. What do you guys think?
Also, have you ever thought about the beginning and how the four benders came up? If you looked hard enough, you would see that Master Paku and Aang was there. There are two other masters on the credits that we'll be seeing, but that will have to remain until a few months(possibly a year or two) to get to those parts.
Like my analysis? I think it's pretty adquent(sp).