This fictional character is written as a quintessential sterotype INFJ.
Ni - The Force is a very Ni concept. It strives for finding the answer without effort or any conscious thought. He never once asked a 'what if' question in 6 movies, evidence against Ne, and was primarily motivated by his ability to focus on the answers he 'just knew'.
In a film such as Star Wars where it's mostly a linear narrative, who has time to insert tiny what if questions into the film for the sake of characterization? That's a poor defining point for INFPs, as INFPs do ask what if a lot, but they aren't Ne dominents, and there are INFPs that don't bother asking and just act on feelings. As for the concept of the force, the force is many things, but I would never regulate it to a box such as Ni.
Fe - Obiwan's feelings were strongly tied to how he felt things should be. The only things that invoked extreme emotions in Obiwan were threats to his world view. Threats against him personally did little to upset him, evidence against Fi. Obiwan's beliefs were secondary to his intuition, and he only acted on them when his Ni agreed.
Hmm, you're right a member of a higher peace keeping order who can through the use of will power get out of almost any situation and whose believed to be invincible will still be upset by threats of violence that he's been trained to deal with since being a child, well not really, only if they are INFP, see INFPs get wound up at everything, even things they've been prepared for.
Courage and emotionally stability are hardly exclusive to any type, and this isn't just an everyday person, you must remember that.
Fe - Obiwan's feelings were strongly tied to how he felt things should be. The only things that invoked extreme emotions in Obiwan were threats to his world view.
It can be also be said that he held those as close values, an internal value system on the way things should be, if only there was a function that cove- OH WAIT!
Introverted Feeling (Fi) is the attitude of judging things good or bad based on how they harmonize or clash with a living being's inner essence.
Hmm, that sounds a heck of alot like what you just said didn't it?
Ti - Evidence that Obiwan was more concerned with how things work can be seen when he interacts with technology, but this is an auxiliary function for him.
Obi Wan wasn't any better with machines then anyone else in the series, in fact that claim to fame belonged to Anakin more then anyone else, and later Han Solo, but Obi Wan never specialized in technology.
Se - Obiwan applies far more preference to what his Ni is telling him than from what he sees in the world around him, making Se is inferior function, but he is one to live in the moment and less likely to concern himself with perceptual details, evidence that he's not Si.
George Lucas was so in tune with the INFJ concept for this character that he cast an actor who is an INFJ in real life to play him in the prequels.
We need examples! EXAMPLES I SAY! BACK IT UP!