Yeah, @iamrl, I wonder about this a lot too, though more on a theory level than on a practical level of typing people. There’s actually a lot of cross-over in this function stack, if one is working with the ‘stellarmaze’ type schematic (and therefore including id and superego functions). It’s not just the dominant and the id that are swapped between these two types, but the whole dominant-inferior pairing and the id-superego coupling. I think it results in a lot of similarities in the descriptions of those two types. If you haven’t already, check out Blake’s article on the Type 3 ENFJ, including the comments section- there’s some discussion of this.
As far as typing actual people to distinguish ENFP from ENFJ, the easier heuristic to use may be the visibility of the aux-tertiary pair. For example, in practice, I try to look for how believably I think an ENFX could pull of being/seeming overpowering and intimidating (especially just by ‘presence,’ not through conversation, status, etc.), or could do the camera stare-down that actors, actresses, and musicians all seem to attempt in photo shoots. Some of them just look demure and friendly, no matter how hard they’re smize-ing. I think XNFPs would have a hard time really seeming legit dangerous. I think it’s also the middle functions that are most of the source of the ENFJ femme fatale attribution, or ‘initiator into mysteries’ role. People I’ve seen typed as ENFPs seem to come up as girl next door; maybe manic pixie dream girl; lovable, non-threatening weirdo.
For what it’s worth, when I first saw/ heard of Katherine Langford (13 Reasons), I also though she was ENFP. She kind of reminds me of the girl in question in the thread “is this gal an INTJ,” who seemed ENFP or EXFP to me. But I really am very bad at typing people, so take that with a grain of salt. Do check out Blake’s article, if you haven’t already.