I was sure I’d answered for this, but huh.
So two things: he really does remind me more of ENFJ sister than INFJ sister. The sisters are both on the introverted side for their type, I guess, which confused the line between E/I for me initially.
Thing two is that I was watching Colin in the first episode of The Living and the Dead and my Fi was like “he’s an island,” which is the actual words that came to me, and I guess means that there was a lot of emotional space/distance (like personal space, but not physical) between him and the other actors. There was a disconnect between how he was acting and how the other actors were reacting to him. It worked well for the role, but it made me question my original impression.
Maybe from the opposite direction, you could also think of it as an introvert amount of projected Fe can make a focal point, whereas an extraverted amount of projected Fe can take over a larger area – shift the mood of a group in a more united way.
Anyway, if I remember correctly, Colin was the catalyst for the mass retyping of the Ns for I/E. (And some of the Ss, but more to come)