I really like this series because it can be approached from different perspectives. I dislike this series because each element pulls me in different directions as each layer vies for attention. Trying to tie it together makes my head spin. At the moment I’m looking at the story with focus on translations.
Some of this had already been considered for a different forum but I might as well post it here as well. Given the direction this thread has taken recently. I would also like to expound on names and nicknames a little more.
It is in the choice and use of names that Suetsugu demonstrated how deliciously duplicitous she can be. I think. She, of course, picked both the names and the nicknames herself. But while the nicknames are translated the character’s family names and given names rarely are. I’m not saying that they should be, but they are worth looking into for the kanji she chose - or could have chosen. This has already been noted in this thread and I'll add a few links later to the comments I had in mind when I typed this.
While I completely agree that you should stop using a nickname once the person has repeatedly asked you to do so, the nicknames aren’t as troublesome to me in Japanese as in translation but that has already been noted.
In the case of Tsutomu Komano that admonition becomes a little humorous, though, because his given name has a meaning which is very closely tied to the reason why he was given his nickname by other characters in the series. Characters who are unlikely to ever call him by his first name. A homophone in Shinobu’s case was already pointed out and at least one exists for Komano as well although that is less relevant in this context, it may be significant in an other.
While it has already been pointed out that Chihaya never uses these nicknames in a derogatory sense and that it may nevertheless be inappropriate for her to persist, there is something else that I didn’t see discussed here before but might be interesting to note briefly.
Taichi on several occasions in this season explicitly used people’s appearance to insult them. In the case of unfavourably comparing Chihaya to her sister Chitose and calling her a boy it is probably written of as childhood banter but I think that comment too contributed to Chihaya’s later personality. The reason why she doesn’t seem to consider herself very attractive can perhaps be traced in part to remarks like those. Although Chihaya herself doesn’t seem too troubled by it in the sense that she doesn’t appear to bear any grudges against Taichi when they reunite.
The second example is clearly not as easily excused but isn’t as clear in the subtitles for episode seven as it is in the original language. That time, well after the time skip, Taichi uses “Chinchikurin” to express his displeasure for Komano’s presence. This is translated as "brat" in the online subtitles. Brat is not as explicitly about a person’s short stature as the Japanese word is, however, and he clearly used it to emphasise how annoying he found Komano upon their first meeting. Not as a term of endearment. Yet someone, in this thread I believe, suggested that Taichi might be the person best suited to teach Chihaya about the inappropriateness of using those nicknames.
Tu quoque, perhaps but because of those two examples I find him unsuitable for that role. If anything, he could learn something from her there because she never says such words or uses the nicknames with malicious intent or to belittle the person she addresses that way. Although both would perhaps be better off learning manners from someone else entirely.
Not that the word Taichi used is so offensive that it can’t be used in public or to imply that it is used exclusively as a swear word, there are restaurants in Japan with ちんちくりん for their name, for example…
I hope commenting on that wasn't beyond the boundaries of what is deemed acceptable in characterisation... Not for the first time, however, I think, Suetsugu-sensei set us up there and a little of that is lost in translation for this season, I think...
Late edit - Manga text added: