Thinking about it, this particular issue perfectly encapsulates the difference between the "find the closest equivalent in the target language" and the "bend the target language to fit the mould of the original language" schools of translation theory. There is obviously a huge amount of cultural and emotional information conveyed by the use of honorifics and, equally obviously, English simply can't do that, so the translator is faced with a choice: do I just lose all this information for the sake of a translation that flows seamlessly, or am I willing to interrupt the flow in order to keep at least some of the information? Indeed, do I regard throwing the reader slightly off keel as a positive advantage because it opens their mind to linguistic and cultural possibilities outside the scope of the target language? I must admit that in my own fic (Nirvana in Fire fandom) I tend to come down on the side of finding the closest equivalent in English - in one, I opted for "cousin Jingyan" as the term used by close-ish relatives because (a) I don't think we ever hear anyone in canon call him any thing but Jingyan, so there isn't a pre-existing association with, say Jingyan-gege, and (b) I didn't feel up to navigating the minefield of who would have called him dage, gege, whatever the Chinese term for little brother is, and so on. It gets a bit harder where in canon a particular honorific is part of the characterisation (eg Nihuang's use of Lin Shu-gege and Fei Liu's of Su-gege), and here I would stick with not translating at all, because that particular form of address is already in the reader's ear and feels almost like a name. But what I absolutely don't want to do is scatter a sheen of minimal knowledge of Chinese honorifics over a fic in a way that makes them distract from the actual story (and would probably end being not quite right anyway. Many years ago I used to be in The Man from UNCLE fandom, and I've lost count of the number of fics I've read where "Illya Nickovetch" would be used as an affectionate mode of address, whereas in fact first name + patronymic is the equivalent of "Mr Kuryakin" in Russian. It would be so embarrassing to commit a similar error with Chinese and I simply don't know enough to be able to tell if I've got it wrong).