I've made this analysis before, but my estimate is ENTP based on the structure and content of his work. He uses Ne to gather a diverse array of raw materials and Ti to synthesize these logically. There are some indications from his personal life to support it, but his music is not a direct expression of his emotional states in the way Schubert's was.
Our modern ears do not hear his music in the context of his time. What Mozart did that was revolutionary was to switch between styles almost measure by measure. He followed the Baroque period in which aesthetics were ruled by the "affections". There were generalized moods and each piece was written to uniformly express one affection through the choice of mode, motives, and overall styles. If you listen to the opening of the Jupiter symphony, you can hear Mozart switching from overture style, to singing style, to sturm und drang. This was shocking and disorienting to his listeners. My position is that this is an example of using Ne to gather a diverse array of musical impressions and then weave these together using the pristine logic of Ti. He also conceived of the work internally. He worked it out in his head before putting it down on paper. His music, possibly more than anyone's, can be analyzed and reduced to perfect fractal patterns using Schenkerian analysis. It is in many ways an abstraction of pure logic.
Those are the cliff notes on Mozart. The facts about Mozart's music are not my own devising. My references are from various texts, and I can look these up as needed. The application to MBTI is my own surmising.