I was just in the middle of translating this myself, damn! You beat me! The only thing I'd say is that Rin says せんせ instead of 先生 throughout the light novel and the manga - that is a particular cute quirk of hers. In mine I translated it as "Sensee." I feel translating it as "Sensei" loses some context there. Otherwise, great job!
@MsCosmicAsh Sorry about that, and thanks for trying to pick it up
Regarding the Sensei thing, I am aware of the difference and the fact that Rin uses the gentler variant. This is a common pattern in Japanese with many words and variations;
お母さん vs. 母さん ("Mom")
好き vs. すき ("I like you.")
頑張って vs. がんばって ("Do your best!").
So on and so forth.
Unfortunately, it's impossible to always capture these subtleties in English without sounding unnatural, such as what you opted for. People are not used to reading "Sensee" as much as "Sensei" -- you'd 99% feel inclined to put a TL note just to clarify that it is not a spelling error or such, and explaining why you did that.
Additionally, differences like this are usual for novels and manga simply because they're literature; people aren't listening to how the characters are talking, so using things like that make the scene and context easier to imagine, but technically, in
spoken Japanese often times there isn't actually a noticeable difference in how you say it (it's not as if Rin is constantly speaking in a cute manner or always making some soft or cute tone change when saying Sensei), hence why I chose to just keep it consistent.
I also didn't want to add a TL note regarding this, because I can't tell if this quirk would change in the future or in specific times (I haven't read the LN, so I don't know about that). To have to note this every time is uhh... yeah.
Note that this is just a personal opinion -- it's how I view the languages and do my translations; you may think your translation is fine or that I'm wrong, and you free to do so. Can't really force my view on anyone, but just explaining my own rationale here since my thing is being read by others, and so they deserve to know what I was thinking when I chose a specific way of saying things.
If you look at page 6 for example, I chose to translate Rin telling Itsuki about the girl as "...My sister." even though she originally said "お姉ちゃん", simply because writing "My Onee-chan." or such sounds off to me in this case. You could write something like "My big sis." but that's far too opinionated (why wouldn't you use "my big sister"? "my older sis"?) and you easily end up with many versions throughout the series that readers may feel lost (I also didn't directly explain the relationship in that bubble using words like "big" just because in English you don't often clarify the relationship when talking about others using terms like that, and the relationship is established very shortly afterwards with the direct Japanese term).
Then, I translated Rin calling out to the other girl (still an "お姉ちゃん" bubble) directly as "One~e-cha~n!" -- using the direct reading here is natural enough as people are very used to people calling to others out with terms like that ("Onii-chan" etc, but not all of them of course; people won't normally know 姪 "Niece", or even more common ones like 弟 "Little Brother"), and it also now establishes things for the readers as for how Rin would be referring to this person everytime "sister" is mentioned and what their relationship is. And elongating with ~ helps match the original way she says it.
But then in the girl's introduction, she refers to herself as "姉" (lit. "Ane"), which is the actual formal way of saying "Elder Sister".
But then, when talking to her, Itsuki refers to her as "Onee-san" as a respectful way of referring to someone else's sister!
As a rule of thumb of my own, I try to use the direct Japanese version when it sounds natural enough and not unreasonable for an average manga reader to be able to distinguish them (Imagine "Onee-chan!" vs "Onee-san!" vs "Nee-chan!" vs "Nee-san" vs "Onee-sama!" etc etc etc RAAAGGHH

).
This way, an average reader would most likely be able to imagine the original tone, level of respect all on their own from the origin, instead of using opinionated direct English equivalents.
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So yeah, lots of yap but TLDR is just that I
do try to be absurdly conscious of differences like that as a non-native, so if I did or didn't do something a certain way, it's almost certainly intentional. As I mentioned in the last page, it is a principle of mine to be extremely faithful to the original tone, so noticing these things and thinking about how to best deliver them is something I invest a great deal of time and effort into!
Thanks for reading! (Both this yap and the chapter) (To everyone else who enjoyed the chapter too!)
