I don't want to badmouth the TL group behind this, tbh, because they usually pulled great translations despite... some choices they have made within the years, but this was a thing that they sometimes did with series that often had chapters that were over 40 pages long - to divide them in small groups and upload them as such. That's why you usually see Chapter x.1 or x.2 and the like here and other series they might have worked with before (they weren't the only ones, it was pretty much common in the early 2000s since not many series divided their contents by chapters or cover and made you guess where it finished). It doesn't help that the uploads do NOT specify which are the unrelated one-shot stories and they just kept going as if the series was continued, regardless.
That being said, though, I don't think the author was actually prepared to work in multiple series at once (if you read through her afterwords, she mentions at the one in volume one? that "she was working in two series at once"). Just because some people can pull it, that doesn't mean you have to overstimate the process, lmao, and it ends up adding up the work you actually want to do. Hence why this series seems a little... disjointed by the end of it (to me, anyways). The unrelated short stories definitely were simply to fill space, because you would need around 4 monthly chapters (around, average 50-smth pages each?) to fill a volume, as well.
I think the "people die" segment is more a personal anecdote from the author when she was younger. Random? Maybe, just to fill some pages given the afterword is also as random because (and she admits it herself), she didn't know what else to fill out, as "I already did my afterword for this other series I was JUST working on 😭"