So I’ve taken a look; my feedback may not be all that helpful, since I lack a lot of the context not being familiar with the characters/situation, so take this all with many, many grains of salt. Text bubble size would also potentially be an issue with some of my suggestions.
ガールズバンドクライ translation feedback
Page 1:
Nana:
それにしても At any rate
まさか私達みたいに因縁のないヒナが I couldn’t believe that Hina, who has no tie to all this [our past with Momoka]
あんなにあの子達を意識してるとはね is so conscious of that girl [Nina] and her bandmates
[These first bubbles are actually pretty hard for me to suggest corrections; without context, I’m reading them as something quite different from what you have here, so I might be completely off base. I do recommend changing that “couldn’t” to “can’t” to match tense, at least. Here’s how I read it, again sans context:]
I can’t believe that Hina is as in-tune with the crowd as us,
despite her being so new. [1]
[1] Really difficult to guess a translation for 因縁のない here for me; I’m reading it as it being surprising Hina did so well despite not having a proven track record, as opposed to the band member currently speaking.
ヒナ? Hina?
Hina:
知てました I know her
知らない子って言いましたけど あのボーカルの子 I said I didn’t know her before, but… that vocalist. girl
友達だったんです. 絶交しましたけど She used to be my friend, but we had a terrible falling out
Nana: え? Oh?
Hina:
損得考えずに突っ走って She was just wildly running in, not thinking of the consequences [lit: loss and gain]
振りかざした正義も 掻き消されて Brandishing “justice”, drowning everything out
[Note: the word in the comic is 正論, not 正義. So I would re-translate as:]
She would just charge ahead blindly without looking at the bigger picture,
ignoring any voiced doubts and
悲劇のヒロイン気取って pretending to be the heroine of a tragic story
馬鹿みたいに不器用で見てられなかった I couldn’t watch her behave like an idiot, making such a mess of things.
[I think I’m with you on this translation.]
Page 2
Hina:
でも、あのとき思ったんです But back then [episode 8], I thought to myself
私の知ってる仁奈じゃないって She wasn’t the Nina I knew back then
[Stylistic suggestion:]
“She isn’t the Nina I know.”
根っこはちょっとも変わってないけど At the core, she hasn’t changed at all, but
一人で藻掻いてたあの時と違う She was different from back then, when she was acting so frantically
[Suggestion; I’m taking a few liberties here:]
At her core, nothing had changed,
but her actions differed from back when she was struggling alone.
最高のパーティ引き連れてラスボス倒して行ってやるって顔で She made a face like she was bringing the highest level party to defeat the final boss
[Continuing on from the previous bubbles; difficult to tell when this took place in regards to the previous, so I’m guessing a bit, and it’s difficult to distinguish between two past tenses with no marker to gauge by @.@ I chose to interpret 顔で as “she acted” :]
She acted as if she was part of an invincible party, on her way to defeat the last boss.
Rin:
それは私達もでしょ? Aren’t we in the same position?
叩かれに叩かれて exchanging blows with each other / both talking big
[Not 100% sure about this either; I have a guess, but it clashes pretty harshly with your proposed translations below. Really just depends on who below is being referred to: the speaker’s band? Or Nina? I’m having a hard time telling without knowing about the history of both. In either case, here’s my suggestion in case it’s helpful:]
It’s eat or be eaten.
Hina:
歌が下手だの、ギターも下手だの、穴埋め要員だの、ダイヤモンドダストのタスト担当だの…! [quoting critics] “Her singing’s terrible, she sucks at guitar; she’s just a fill-in; she’s responsible for the ‘dust’ in Diamond Dust”…!
Rin: どうどう nice imitation / let’s not get too worked up
[Difficult to say without knowing that character’s personality. I’m inclined to lean more towards the “calm down” interpretation though, given the lack of kanji. Suggested translation:]
There, there.
Ai: それでも…私達はここに立ってるんだから Despite that, we’re still standing here together now
Hina:
そうですね Yeah, you’re right
あの子とは…「友達」なんて簡単に関係には戻れないかもしれないけど Me & her - we probably can’t simply go back to being friends again, but
最高のライバルにはなれる気がします I feel like she’s become my ultimate rival now
[I’m mostly looking at that なれる there; feels like Nina hasn’t become the rival yet, but may/can/will. Again, context may change that.]
I feel like she’ll become my biggest rival.