i think one of the ways i make sense of it is the fact they wouldn't exist if it weren't for them as a group in the first place. in the case of me writing about jwk frequently: i didn't have that name until that one behind the scenes video where they spoke about it, and so bc it's a thing nmixx formed themselves it feels attached to them. as well i think there's also a level of suspension of disbelief where sure, visually i know i'm not directly writing jinsol when writing, say eddie for example, but i know eddie exists off the back of jinsol and therefore is technically jinsol.

in the times where i have thought about writing prom party specifically, they already had their own sort of personalities (austin being referred to as misfit, travis football captain, bella and eddie not gaf-ing about eachother whatsoever etc.) which id try to present in a fic. to me, they exist as an extension of nmixx - a chance to mess around with personality, dialogue, character interaction and so on, even if it isn't strictly 'right'.

the saja boys thing is sort of different in the sense that they were mocking the literal ones for a joke bit and didn't really expand on it further. in the case of using the names for genderswap reasons, take "garden of eden" for example, while writing jiwook i was also running the dialogue through my head as if i was normally writing jiwoo to see if it would make sense, but also changing some bits to fit the jiwook-ness of it.

the appeal, at least from a writer perspective, is just being able to do something different or fun that isn't overly serious. ofc i could write a yaoi fic that is serious and is meant to have the same sort of care and weight id put into a f/f fic, it'd just be that id write them as guys. i don't expect genderswap, m/m, or f/m nmixx to be liked by everyone - it is kinda just a niche i personally enjoy and find that a handful of others around me also enjoy. and that's maybe why im okay with them not being direct translations of nmixx and being their own 'things'; bc they sort of are their own things. i think ive been in this line of thinking for long enough where i can go "that's so jiwook" to one thing and "that's so jiwoo" to another. it's a feel thing. sort of.