I apologize, I don't know how to break up quotes so I will answer with a list of responses.
1. Acting like an extrovert: This seems fairly accurate to me. I have spent a great deal of time developing my weaker sides, which were: Communicating with people, social customs, appreciating people, opening up emotionally, learning the world doesn't evolve around me. I used to avoid any kind of interaction with people, but now I am (or so it seems to me) equally energized AND drained by BOTH other people and introspection.
2. Terse...is that a good or bad thing? I was mostly pressed for time as I was answering.
3. I have looked into about half of the information you provided and I can say that Kiersey's analysis of an NT described me by about 90%. (I easily identified with most of the info, but a lot of it reminded me of myself before a lot of personal development.) In fact, I became very excited with how I identified with NT.
I read up on the INFP and INFJ types and I found that I couldn't really identify with them. If you want me drop some specifics about why I feel this way, let me know.