Chapter 79
p2: I don't know if these are supposed to be specific characters, or just general stereotypes. Miu seems to be dressed like a bōsōzoku, a member of a Japanese bike gang. Her banner says "Kenka Joto" which is literally "Superior at fighting" but roughly more like "Come at me." It looks like Chika's armband says 風記, but I think it's supposed to be 風紀, which is something like "moral order," but you can just think of it as "Hall Monitor."
p5: In case it's not clear, these phrases are all anagrams. I felt like trying to do the same thing in English would have been too much effort, so I just translated them directly.

Chapter 80
p5: I'm not sure if I'm translating Miu's line in the 4th panel correctly. いや、特に何も無いんだけどさ。Roughly, "It's nothing special."
p10: I never really noticed it before, but apparently sunglasses are considered a foreign thing. Japanese people tend to not wear them.

Chapter 81
p1: For those unfamiliar, they're celebrating Tanabata, a summer festival on July 7th of each year that celebrates the one day a year when the mythical figures Orihime (representing the star Vega) and Hikoboshi (representing the star Altair) are able to cross the river separating them (the Milky Way galaxy) and meet. It's traditional to write a wish on a special slip of paper and tie it to a bamboo stalk.

Chapter 82
p1: In the original, they were discussing how most Japanese people mispronounce "avocado" as "avogado." And then Miu mentions a place called "Ibaraki" which is apparently often mispronounced "Ibaragi."
p5: I think the title page is a reference to an old Japanese song called "Found a Little Autumn."

Chapter 83
p1: I'm not sure what the 8銭 in the graphic at the bottom means. I know 銭 is 1/100th of a yen, but that seems like it should go with the 39 above (2.39 yen per dollar). The gist of the joke though is that 2 yen per dollar is a ridiculous exchange rate, since it's usually in the range of 80-120 yen per dollar.
p4: In Japanese, the word for "pigeon" and "dove" is the same (which makes sense since they're both kinds of doves). Another name for the pigeon is the "rock dove," so I had Ana call it that to make Nobue's comment work (and Ana is so proper, it makes sense for her to say something like that anyway).
p7: While looking stuff up to translate this issue, I came across this video. https://www.youtube.com/watch?v=N1-hz6Fu2bw [[魔女軍団ステファニー - ハトのマジック]] I'm not sure if this chapter is a reference to this group in particular, or if the similar elements (the outfits, the music) are just generic "magic show" stereotypes in Japan.
p12: This is one of those rare situations where the English translation works exactly the same, if not better than the Japanese. The text at the end is literally, "There are no tricks or contraptions," a stock phrase usually heard before performing a magic trick. The English equivalent to this is "Nothing up my sleeve," which just happens to fit beautifully here.