Itachi is an INFJ, much like Minato, and possibly Nagato. His whole plan to save Sasuke was Ni-Ti based. His method of going about it definitely shows Fe over Te. Trying to passively beat another person at their own game is an Fe trait, and the fact that he thought Danzo's method to be the only way of saving Sasuke goes against Te's desire for efficiency.
INTP's wallow in self-doubt far more than Itachi, due to the Ne aux, and so, such an traumatic ordeal would haunt Itachi forever, causing him to constantly reanalyse the correctness of his actions and look towards the outside world for assurance that he is following the right path. Yet Itachi never wavered in his conviction, or following through with his decision, with the safety of his brother being his sole motivation (Fe aux). He is also less direct and harsh in his speech than Te users e.g like Sasuke.
Sasuke is harder to type. I see both ISTJ and INTJ in him, with a strong amount of reasoning for both. However, I am slightly more inclined to ISTJ than to INTJ.
@Numinosity I agree with most of your points for Sasuke being an INTJ, except a few of the Ni ones. Revenge was never Sasuke's idea in the first place, it was the words of his brother that invoked that. His only added motivation was to restore his clan.
Many of the actions Sasuke took were based on the information of his view of the experience. His revenge plan was a good example of this. Sasuke never sought out information about his clan's massacre and only relied on his experience of how the sequence of events played out. This indicates dom Si. He was only interested in Itachi's story once it was mentioned by Tobi. Even so, after that, he went straight back in for revenge against the kage, still not seeking to understand Itachi. This shows an inclination to Si over Ni, as he prefers to act on this information he has obtained (Si), rather than piece it into his overall plan (Ni).
His motivation to learn about Itachi more came much later in the series, after meeting Itachi and that was to find his answer to what he would do post-Itachi. This could be interpreted more as a tertiary Fi action, rather than an dom Ni action.
Many of Sasuke's plans are based on his semi-immediate experience, (Si) fueled by his strong emotions (Fi). He had no escape plan after attacking the Kage summit, and actual plan of attack. He relied on his adaptation alone to fight the kage, aligned with his skill, rather than devise an overall plan to pinpoint his objective. His plans lack considerable insight, and are rarely ever future oriented, especially when you compare him to true Ni users such as Itachi or Minato.
There are quite a few more points for Sasuke being Si dom but I'll end it here for now.
