Excellent points... and yes, most Enneagram Enthusiasts do not have an expert level of understanding of the MBTI and vice versa which brings its limitations..... The same is true with the instincts, trifix, tritype, micro expressions, archetypes, lexicon, etc.
And as we all know, the author(s) and teacher(s) with whom a student has studied...Enneagram greatly influences one’s definition of type, instinct, tritype and MBTI. For example, most early authors didn't know the instincts, and some had much of type 9 in type 2, social instinct as type 1, much of sp as 8ish or 6ish, sexual as 4ish ...
So, I see these as different templates... Once I understand the template a person is using I better understand why they type individuals they way they do. We naturally type according to our knowledge base and experience. For example, depending on the description of the types used in any of these systems, we can better understand why people type differently. Fortunately, there are some exemplars that are more universally agreed upon…. Among other things, I track the patterns of consistent outliers and interview further to find the meaning.
This is why I am more focused on the patterns that emerge…. I seek confluence.
For example, on the first Enneastyle Questionnaire, under the question I need ______, the sp 9s said they needed elastic… funny joke, yes….but it was very revealing in that only the sp 9s made that joke…. so it became meaningful as to the internal world of the sp 9 and lead to deeper insights. Ease and comfort was the answer of course but I then compare and contrast the different categories to verify the potential types with a greater degree of accuracy..... Once I have a template as to how people "self identify" I then know the categories I wish to further clarify and pursue. I also cross reference data.
What 5 words would you suggest are the most frequently used by the 16 MBTI types?