That is correct, but I’ll mention, that that’s not 可愛い, you wrote there 
This is another case of the る → ん slang. The original is
見せつけてくれるじゃないか
Your translation seems correct, though I’d translate it as “Showing off, aren’t we?” if I wanted to keep it natural.
Thanks again, and yeah oops on that kanji! Although, she is KIND of scary sometimes 
Thank you very much, all clear now!
Next question:
しっかし志木守さんなんでもっとイケメンと付き会わなかったんだ?
‘But why can’t Shikimori-san date someone cooler?’
和泉ヘタルだしな
‘Izumi isn’t up to it, huh?’
お前も俺ら側だろうが!
‘You’re on our side, too, aren’t you?’
I am not sure who’s saying the last phrase and to whom? Or maybe I am mistranslating something?
That’s almost correct, but there’s nothing here saying “can’t”, rather this is a “why isn’t”. “Why isn’t Shikimori-san dating something more good looking?”
Typo there, it’s ヘタレ, if you’ve ever seen or heard about Hetalia, this is the word the name comes from, “lazy” “klutz” “good for nothing”.
I’d translate this as “And Izumi is such a good for nothing”
All of these pharses are said by generic lackey x, y and z respectively. And they are ganging up on Izumi, kinda saying these to him, but also to each other.
Thanks a lot and good catch with the typo! Also, I’ve just googled Hetalia and learnt something more. 
Panel 1
Classmate - 不幸体質の地味メン和泉クン！！
I think this would mean something like “Why the long face, Izumi?”, to use an English idiom. Literally “unhappy constitution sober-faced Izumi” UPDATE: nope, I’m wrong 
more like they are just making fun of him as a “plain guy with an unfortunate disposition”
[laughter of peers in background]
Panel 2
Classmate - カワイイ彼女に迷惑かけんなよ （にしてもシイてねーな）
I can’t make sense of this one… fell back on translation app which gave “don’t bother your cute girlfriend”, which doesn’t seem right. Will check posts here for help. UPDATE: yes, something like “don’t be a nuisance to your cute girlfriend” - essentially making fun of him
Izumi - ウッ。。。（情けない）
Ugh… why me? (literally: pitiable-not sure if my interpretation is correct. Btw just learned this phrase on WK last week. Love when that happens!)
Panel 3
Classmates? - しっかし 式守さん なんでもっとイケメンと付き合わなかったんだ？
But why doesn’t Shikimori go out with a cooler guy?
和泉ヘタレだしな
Izumi is so sloppy (not sure about the しな ending–will check comments)
お前も俺ら側だろうが！
Seems like you are also taking our side right?! (not sure of が function here)
Izumi - … (speechless)
Panel 4
Shikimori (Background characters in shock) - おまたせです（かえりましょ）
Thanks for waiting! (let’s go home)
Izumi あ うん
oh, right
Panel 5
Classmates talking - ヤベッ やべー 。。。聞かれてねーかな。。。
No way! I wonder if they heard us… (I haven’t really studied ‘passive’ verb form yet so had to look this up)
Shikimori and Izumi (backgroung text) - later!
Panel 6
Classmates? - いや へーきだろ。。。
Nah… it’s ok right? (not sure of nuance here)
し - I think this is the conjunctive, 〜し for "Not Only…but Also…" - specifically, indicating that “(a reason for Shikimori to go out with a cooler guy is because) Izumi is such a good-for-nothing”. A good video on the “reasoning” aspect is How to Use ～し
な - I think this is a more masculine version of the sentence ending particle ね
I was also not sure at first but I looked around and it seems like it can be used for emphasis - particle が - What is the meaning of the 「だろうが」 in 「仲間だろうが！！！！」 - Japanese Language Stack Exchange
式守さんて全然怒らないよね
I am not finding an expression hit in my google search.
Does it mean not ? as in ない. What does the ら do.
I am correct that ら is not part of ない
you’re slightly missparsing that, the word there is 怒らない, which is the negative of 怒る, “to be angry”
Thank you this will help!
Thank you! I love that guy’s videos–hadn’t seen this one. His sense of humor is great!
Panel 1
Shikimori - ジロリ
[staring intently] I have noticed this more often expressed as じーーー Seems like this is Shikimori giving their classmates the “evil eye”
Panel 2
(background text) - 怖ッ 。。。でも (background) ヒエッ
[scary…“but” … shivering]
Panel 3
Classmates - ちょ。。。ちょっとかっこいい
(but she’s…) pretty… pretty cool (honestly not quite sure who’s talking to/about whom here)
Shikimori - 。。。私 ちょっと心が狭いのかもしれません。。。
I’m a bit narrow minded perhaps…
Izumi - それはないと思うけどなあ
I don’t think so (けどなあ maybe used here to soften the statement/indicate his opinion)
To expound a bit, 迷惑かけんなよ ＝ slang form of 迷惑かけないよ = 迷惑かける ＋ ない ＋ よ
Since it follows on from the 。。。でも, the subject is still Shikimori and the speakers are still the classmates thinking to themselves.
Looked at this above, but it’s basically him saying “I don’t think so (but sometimes…)”. それはないと思う = I don’t think so, けどなあ = “But…”.
Shikimori - 。。。私 ちょっと心が狭いのかもしれません。。。
What is のかも doing here? Also isnt しれません saying “… isnt known”? Something like “why they are narrow minded isnt know to me?”
It’s の as a placeholder for a noun, similar to the function of “one” in English (i.e. “Please pass me that book. The blue one”, here “one” is substituting for “book”). In this sentence it’s probably 人, I guess?
And then かもしれません, “perhaps; maybe”
Also, 私 is the topic of this sentence, just the particle has been omitted. She’s talking about herself.
P.S. Welcome! 
Ahhh okay thank you. I am definitely having trouble discerning where words stop and start
And week 3 thread is up, as they say, it’s certainly Saturday somewhere
Had a hard time understanding this chapter, so I’m grateful for everyone’s discussions!
How did I completely miss the blackboard eraser sitting on Shikimori’s head?? It made SO MUCH MORE SENSE when I went back after looking at some of the questions here.
Me: Blackboard eraser? What blackboard eraser?
/Flips back a few pages
…Oooooooh