I know that it has been tried over and over to find some relationship between enneagram and the mbti/jcf, and so far, nothing conclusive has come out of this.
However, I want to take a broader approach and see which DOMINANT cognitive functions just can't match with some enneagram types.
Here's something I can throw real quick:
1: Se, Ne
4: <I can't see a 4 being something else but a Ji-dom tbh>
5: <Any type of extroverted function whatsoever>
6: <No relationship. I can see any JCF type being a 6>
7 + Ti is easy to explain. 7 fears his own head, and will avoid deep pondering about an issue unless he's mandated to do so (and even there, it will only be a very superficial scoop of subjective logic). How can this mesh together with the Introverted Thinking type beats me.
The reason why I can't see a 9 being a Ne dominant is because 9s are the most safety-oriented type out of enneagram. Type 9s, at the root, care about having a comfortable and undisturbed life. Helen Palmer constantly explains that 9s are often prone to fall into a routine in which they neglect their inner demands. They over-adapt to their surroundings, and constantly try to create any upsetting in their environments. "We work collectively", "United we stand, divided we fall", and many other phrases similar to this resonate deeply into the heart of a 9. I am trying to be as concise as I can here (however, not entirely vague), and my point is that 9s will only act out of self-desire in extreme measures, and will always choose a life with a secure routine if given the option.
Now, what is Ne about then? In short, the Extraverted Intuitive type is primarily drawn to the possibilities. An Ne-dominant will NEVER accept an environment with limited resources, and to have a constant routine is life implies some sort of slow-suffocation. Their whole life is about new situations, about new upbringings. A Ne-dom person is constantly bored with familiarity, and will constantly be the initiator of new projects in his/her life.
It is easy to see that both these types will clash because of their lifestyle. 9 desires security and over-adapting, Ne requires possibilities and to be allowed to initiate... together, you have an oxymoron.
What are your thoughts on this (very incomplete) list? Any additions?