I gotcha on the season-focus; I just meant that if we're to compare who-gets-what per teachers, I think it's important to note that each character's find-a-teacher was treated differently. Toph doing it herself, Zuko learning best when learning in tandem, Sokka needing a teacher who'll focus on him exclusively (if for only a short time), and Katara seeming to learn a little bit from just about every person she meets. Aang in this case is obviously the oddball, since he ends up with a variety of teachers, but in some ways the different learning styles of the others also inform their styles when it comes to teaching.

Although I have quibbles with some of the specifics for each (some of which align with what you mentioned), I can see how the writerly method might have gone. It's almost like the ideas might've been planned out in context of "what are the different ways a kid can learn, so we can show that each style has value?" and then a style assigned to each character in the planning.