Wind Up Rex or @andante (who appears to have left this forum without a word...if you ever see this andante I miss you ).
Anyways for ESTJ...I think he prioritizes the implications behind past experiences and the "correct" way to do things. Like that thread he started asking how to propose to his girlfriend...he just seems to be a very protocol-oriented person. I know there can be traditional NTJs (like Kullervo even though he's convinced he's an INF 4) but he just doesn't strike me that way. Why do you think he's ENTJ?
I don't think 3s give off a particularly SJ vibe. They don't always try to impress others by appearing traditionally impressive - 3s will be whatever 3s want to be. Disco probably just likes to impress others by appearing like a successful all-american boy...oh now I see what you're saying.I think the SJ vibe people get from him is because he is a e3. That I think he is. I am willing to bet a lot that he is an E3.