By “subtype” do you mean the person places heavy emphasis on their second instinct? I haven’t heard that term before with the instincts.
Thank you for sharing your experience; interesting what you noticed in your group of friends about having the same flow as the mother and having her blindspot as your dominant. I hadn’t noticed that before but it’s true of me. When it comes to my closest friends it’s more of a mixed bag.
At the end of the day I don't really know, but I’m an IEI as well so my brain goes, “ooh! a pattern! What can I theorize from this…” and I always like gathering more patterns from others.