(Disclaimer: This is obviously not a theory of the real Mozart’s mbti, only the characterization of Mozart in Amadeus.)
Se: Mozart’s genius and creativity was due in a large part to his childhood spent traveling the world and experience of different musical styles, which he absorbed into his own personal style. He has a tendency to overindulge in alcohol, and adores partying, which is the only thing that can distract him from his music. He’s observant enough to play Salieri’s composition after hearing it once and can improvise it to be better almost immediately. From childhood he was performing and clearly loves being the center of attention. Because of this, he makes a lot of crass jokes and sexual humor, which are funny to his theater friends (such as Schikaneder) but less so to the Vienna elite. While he’s aware he’s the best composer in Vienna, he doesn’t seem to care about his reputation as a child genius and only about his present concerns.
Fi: Mozart is aware of what he feels personally, following his carefree whims and his personal musical interests. He pushes controversial storylines for his operas because he likes them personally. Numerous times he refuses to compromise and write according to what his employers want, in favor of something he believes is his best work. He stays in Vienna and marries the woman he loves rather than obey his father’s wishes. He wants to please his father, but also refuses to move back to Salzburg, ultimately choosing his own vision of his music over his dad’s. Even though he cares about his wife and father, he tends to express how he feels about them, rather than percieving their emotional needs.
Te: Mozart isn’t shy about his opinion, another reason his career doesn’t really get off the ground. He is extremely honest about which composers he thinks are good and which are crap without consideration for other people’s points of view. His vision of good music is well articulated and extremely blunt and he demonstrates repeatedly through practice that his ideas about music are correct. However he has pretty bad Te in general. He is convinced his music is excellent and has trouble understanding why that doesn’t translate into a successful career, failing to see the additional steps needed to become a success. He procrastinates on work when on the brink of poverty and falls into substance abuse. He is aware that Salieri has achieved the career success he desires for himself, however he doesn’t really see how to get to that level on his own.
Ni: Mozart shows well developed Ni in his craft. Though Mozart is creative, he isn’t shown experimenting a lot with different directions for one composition. Rather, he is shown knowing exactly what he wants his compositions to sound like and writes them down, wasting little time with other alternatives. His compositions tend to be spotless with no corrections, showing a well articulated idea of what he wants to achieve. His vision is so strong he’s certain that his work will be absolutely amazing even if the work only exists in his mind. When creating music he can focus intensely on writing and become oblivious to his surroundings.
He’s a lot less effective at applying Ni to life and understanding the consequences of his actions. For example, he can percieve Salieri dislikes him but misinterprets it as contempt rather than jealousy.
ESFP vs ISFP: Mozart seems to have well developed Ni for his creative process, good enough that it appears to be a tertiary rather than inferior function. I made the call because his Se was extremely well developed. From the very tiny glimpse we got of his childhood he was an Se dominant performer first, playing the piano blindfolded, etc, and tended to conform to his father’s wishes. I take this as Fi developing later, rather than first.