Would we be able to play an AU brought in from the spirit vines/spirits from a different timeframe within the canon? For example, an AU character but during the timeframe from when Aang disappeared(/froze himself).

Edit: I realized I have another question! If we were to canon update a character, even though they return in the same position they left would their clothing, hair, etc be updated too? Like Ty Lee, if I updated her to at the end/after book 3, would she arrive in her Kyoshi Warrior gear if that's what she was wearing?