I tend to agree with the original poster's assessment of Fi / Fe. (or at least my interpretation of her interpretation! lol) I think the differences between Fi/Fe and other traits (Ni/Ne, etc.) are very interesting. I do think that Fi's and Fe's tend to "click" with each other, and I notice that especially whenever I'm around an INFP or ENFP friend (I'm an INFJ). It's almost like I'm looking for someone to nurture and appreciate, and they're looking to be nurtured/appreciated. Don't know if that's coming across right, so let me try another example:
I also find that I tend to click with ENTPs and INTPs (types that many sensors find quirky, outlandish, or over-the-top) because my introverted intuition is a good match for their extroverted intuition -- I find their humor and comments insightful and hilarious, and they seem to appreciate someone who can catch the crazy ideas that they like to spout out.
Back to the Fi/Fe dichotomy, I'm glad someone started this thread because I've been very curious about the differences and similarities between Fi's and Fe's for a long time. My random observations on introverted feelers versus extroverted feelers are that introverted feelers can keep their emotions hidden much better than extroverted feelers. Growing up their were many times my feelings were hurt and I would try desperately to hold back tears but it was hopeless, my feelings showed right on my face for everyone to see, and people could often spot immediately when I was upset, even if I tried to hide it. But I've noticed that my introverted feeler friends can remain stoic and emotionless during something that would upset me. Afterwards I tell them I don't know how they stayed so calm and collected, and they tell me they weren't, that they felt awful inside but it just didn't show. Also, I hate to admit it but I feel very upset and anxious when people are unhappy or angry with me for whatever reason, and I often obsess over whether I unintentionally said something rude in a social situation. My introverted feeler friends do not seem as bothered when someone is angry with them. It is as though their feelings and sense of well-being come from their inner being, while mine come from my interactions with others. Just some thoughts!