Wow, this thread is still alive! Here I shall make my third post on this forum for over a year since my first two - all on this one topic. xD
It's interesting to see that someone finally agrees with my analysis of Zuko as an ISFP. He's kind of an anomaly and rather complicated compared to most of the other characters, but I think we can all agree he is firmly ISxx. With Zuko, I think it's helpful to look at the specific Cognitive Functions rather than the individual letter preferences. Of these, we can clearly see that he uses almost exclusively Fi (initially suppressed), Te, Se, and to a lesser extent Si. He seems to have no ability, or desire, to use any of the other functions. So all we need to do is find an ISxx type that utilizes at least three of these functions and includes two of them as the dominant and auxiliary functions.
Zuko's motivations are conflicted between his moral code (Fi) and his desire for approval, primarily from his father. Growing up in the harsh, militaristic Fire Nation - which encourages more of a Te mindset, aggression and forth-rightness - Zuko tried to suppress his Fi, especially after being banished and rejected by his father. After his banishment, he is shown using an underdeveloped Te to give orders and such while trying to capture the Avatar, which I believe is his inferior fourth function. His use of Te is raw and unnatural, seen for example in "The Storm" in Book one. Giving orders just doesn't seem to come naturally to him, especially compared to a character like Zhao (ESTJ imo), who could be seen as sort of a foil to Zuko. I think that despite seeming raw and uncontrolled, his Fi is his dominant function because it is what ultimately drives him. Because he supressed it until later in the series, he is (usually) unable to express it in a positive manner. As for the auxiliary function, it seems clear to me that it should be Se. Zuko is adept at using his auxiliary Se to get himself in and out of scrapes and for short term plans, for example when he tries to capture Aang as the Blue Spirit or when he infiltrates the Northern Water Tribe. So, Fi > Se > Ni > Te=ISFP. He certainly doesn't fit the ISFP "artist" stereotype though haha, not that it matters.
Iroh is another tough case. His greater experience and wisdom mean he's probably skilled at using most if not all of the functions. As previously said, he's a balanced character. I think it's clear Iroh is some sort of ExFx. I can see him as both an ESFP and an ENFJ, but not really as an ESFJ or ENFP, though I'm not exactly sure why. I think Orangey made a good point about Iroh's hedonistic sensor tendencies being, in general, more related to his enjoyment of simple physical pleasures rather than his innate personality preference. However, I'm still not convinced he's an N, and I think he does display Se tendencies. More importantly however, is that he just acts so blatantly like a Perceiver. Iroh is all about relaxing and taking things as they come without a care as long as you've mastered yourself. He is very laid back, and I remember very few times in the series where he displayed judging tendencies. Honestly, I think a mature ESFP fits him quite well, but he does seem to have the "Wise Benevolent Teacher" NFJ thing going on as well.
As for Toph, I say look at the functions again. Would you say that Ti or Se appears to be her dominant function? I think it's clearly Se. However, she is rather Stoic, while ESTPs are usually more fiery. Overall, she doesn't appear particularly Extroverted or particularly Introverted. I'm not completely convinced on either type for her, but just by looking at what her dominant cognitive function appears to be, ESTP seems to be a better fit.
I'm also starting to agree with Orangey about Aang; I admit he does exhibit Se much more clearly and more often than Ne. The debate on his type reminds me of the debate over the same two types for Luffy from One Piece. I don't really watch the anime, but they do seem pretty similar in this aspect. Also, Orangey, didn't your type used to be INTP?
