Midoriya would initially be in shock. But then, his heroic instincts would kick in. He might try to analyze Toga's behavior and find a way to use it against her. For instance, if he notices that she gets distracted easily, he could create a diversion. He would also be thinking about the safety of others. He might worry that Toga has some bigger plan that involves harming his classmates or the city. So he would be constantly looking for a way to not only escape but also stop Toga's potential evil plans. And throughout all this, he would be drawing on his training at U.A. to keep his composure and think rationally.
Deku might be completely shocked at first. Since Bakugou has always been so aggressive towards him, he would never expect such a confession. He might just stand there, mouth agape, not knowing what to say.
He might cry a lot. Deku is very emotional, and being cheated on would be a very painful experience for him. He could also get angry, which is rare for him, but this situation would be so unjust that he might not be able to hold it in. He'd probably start to question his self - worth too, thinking that there was something wrong with him that made his partner cheat.
Deku might be initially shocked. He's used to Bakugou's aggression, but an actual injury is different. He could be in pain and disbelief at first. Then, he might try to downplay it, especially if he doesn't want to cause trouble for Bakugou, because Deku is generally a very forgiving character.
Midoriya's family would be ecstatic. His mother would be busy helping with the wedding preparations, giving advice on everything from the dress to the food. Uraraka's family would be equally happy. They would see Midoriya as a kind - hearted and strong young man. Her mother would likely bond with Midoriya's mother over the wedding plans, and the two families would come together to celebrate the union of the two young heroes.
Well, some might be really amazed. They could see a new side of Deku that they never knew before. His singing might show a different level of confidence or a hidden talent, so they would probably cheer him on.
Some characters might try to understand Deku's motives. Kirishima, who was close to Bakugou, would be angry at first but might also try to find out if there were any extenuating circumstances. However, many would be afraid of Deku, seeing him as a threat now that he has killed one of their own.
Uraraka would be heartbroken. She was one of Deku's closest friends. She might lose some of her usual cheerfulness and become more focused on finding out who or what was responsible for his death. She could also struggle with her own self - confidence in using her quirk, as Deku was always an inspiration to her.
The other characters' reactions would be diverse. Bakugo might initially be very confused and maybe even mock Midoriya a bit, but deep down he'd still see her as a rival. Uraraka would probably be very empathetic and quickly become a good friend to Midoriya in her new form, helping her with things like getting used to the new body. And All Might would be very supportive, seeing it as just another obstacle Midoriya has to overcome in her journey to become a great hero.
Other characters' reactions can vary widely. Some of the more empathetic classmates, like Tsuyu, might offer words of comfort and stay by his side. Mineta might be a bit more cowardly, but still show some concern. The teachers, such as Aizawa, would take charge of the situation. Aizawa would ensure Midoriya gets proper medical attention and also start an investigation if the injury was due to foul play. His mother, if she were to find out, would be extremely worried and rush to be by his side as soon as possible.