Kirishima would probably support Bakugou. He respects Bakugou's strength and no - nonsense attitude. He also doesn't like Mineta's pervy behavior, so he might think that Mineta deserved it. Kirishima would see Bakugou's action as a way to keep the class in line.
Well, without reading the fanfic, it's hard to say for sure. However, given the title, perhaps Mineta has done something to annoy Bakugou, like making inappropriate remarks or actions. Bakugou, being his hot - tempered self, decides to kick Mineta, and the window might be involved either as a target or as a result of Mineta crashing into it. It could also be part of a bigger story in the fanfic world where there are consequences and further developments based on this incident.
Well, it could be that Mineta was being his usual pervy self around the girls, and Bakugou, who can't stand such behavior, just snaps and kicks him out the window. Maybe Bakugou has been warning Mineta for a while, but Mineta doesn't listen. So in a fit of rage, Bakugou uses his explosive power to send Mineta flying out the window.
Well, in bakugou x midoriya x todoroki fanfiction, often you'll see complex relationships being explored. Their different personalities play a huge role. Bakugou's explosive nature, Midoriya's determination, and Todoroki's cool and conflicted self. Writers might focus on how they interact in various situations, like during training or in the face of danger. It could also explore themes of friendship, rivalry, and how they grow together as characters.
Mineta could be redeemed in a 'bnha mineta redemption fanfic' by having a character development arc. He might start to engage in more heroic deeds. Like, he could sacrifice his own safety to protect others during a battle. This would show that he is growing and becoming a better person, which would lead to his redemption.
Mineta could react with a mixture of embarrassment and defiance. He's a proud character in his own way. So when All Might yells at him, he might try to put on a brave face and argue back a little. But deep down, he knows he's in the wrong. Eventually, he'll break down and start crying, realizing that he has disappointed not only All Might but also his classmates who are all striving to be heroes.
One popular theme is friendship development. Given their different personalities and initial relationships, it's interesting to see how they become friends. Another theme is power growth. As they train and face challenges together, their powers evolve. For example, Bakugou learning to control his anger to better use his quirk, Midoriya getting a better handle on One For All, and Todoroki fully embracing both sides of his quirk.
Often, in momo x bakugou fanfic, there's a contrast between Momo's calm and intelligent nature and Bakugou's fiery and aggressive one. This contrast creates a lot of interesting dynamics.
Often, in 'uraraka x bakugou fanfic', there is a lot of emotional growth. Bakugou might learn to control his temper better because of Uraraka, and Uraraka might become more confident in herself. The fanfic uses their relationship as a vehicle for personal development for both characters.