In the first place, an ENTJ's "unhealthy state" would be anything but a loner state.
He was unhealthy either way in the beginning and that was when he was a loner.
being suddenly more externally oriented does not mean it is his preferred state.
Yes, but he's clearly more comfortable and healthy that way.
An Inferior Fi is more about the lack of emotional concerns rather than overly obsessing one's own concerns. An ENTJ with Inferior Fi problems is one that proceeds according to the plan without considering the emotions at play. Being overly attached to an ideal of a team is more of an NiFe issue. On the other hand, the ENTJ's issues are about detachment.
That's when Fi is being ignored because it's in the inferior position. When Fi is pushing on stressful ETJs it can cause them to be unfairly controlling with hidden (or not-so-hidden) agendas. I've heard my go-to ETJ buddy [MENTION=4945]EJCC[/MENTION] talk about that quite a few times I think.
There's no official "In Charge" type, but there is a dichotomy that refers to something similar which is the J vs. P. All J types have preference to be "In Charge"; this includes the INTJ(the Mastermind) and the INFJ(Counselor). The difference between these two is that the latter is more emotionally involved which Kageyama is.
Interaction Styles
But I'm assuming you mean Directive vs Responsive (with STPs and SFJs being the exception to each). But Kageyama is clearly In Charge over Chart The Course to me. If you can't agree with me on that then we're never going to agree on his type and discussing this further would be pointless.

I agree he's Directive at least.
For me, Tsuki is ENFJ. I don't know about Kenma. I think you misinterpret Fe as a "soft" and passive function. Tsuki's primary motivation for bullying Kageyama can be found in Fe. He hates the elitism and the social values revolving Kageyama's and his fame of being a prodigy.
No I don't and I don't know why you bothered to say that. I know Fe isn't soft. Tsuki seems like a clear introvert to me, even with the reasonable misanthropic extrovert idea you've suggested. He just seems so/sp to me from what you've described.
Kageyama's control issues comes from his ideals and his simple desire to win. That requires maximizing efficiency is not necessarily related to preferring Te. It's more about being emotional rather than being bossy that indicates that Kageyama is a Feeler.
Feeling =/= emotional. End of story.
I still think he is too moved by idealism and all that camraderie talk between them about not giving up. He might not have many clever ideas but he is overly inspired and focused on that stuff. Maybe you'll see his what-ifs later on.
How is this a preference for intuition though...What you just said sounds like E7 to me.
Most anime main characters imo are NFs.
I don't agree with typing by majority, but there are plenty of ESFP main characters. Ash Ketchum, Naruto Uzumaki, Usagi Tsukino, etc. The only ENFP anime MC I can think of right now is Sakura from CCS.
It is now.
