And this is why I hate these review spoilers. It would've been fun to theorise what Koutaro is gonna do with the letter. But now there's no point in doing so...
yeah, definitely no consideration for the reader on that part. I mean, we could all guess easily that Kotaru accepting the letter so easily means it wasn't for him, esp from some no-name out-of-nowhere girl, but still ruins the surprise of who/what it was for.
Student committee responsible for keeping the school looking nice, most prominently by taking care of the decorative plants (whether in outdoor flowerbeds or indoor vases) and picking up trash.
I guess if the scanlator's intention was to get me to skip their donation/ad page at the end every time they have succeeded, putting one panel spoiling the next chapter is really dumb.