Dumbledore would be a key figure in the reactions. If he believed in Snape's innocence, he would try to find a way to free Snape while also not alienating Harry. He might start his own investigation to uncover the truth. The other Hogwarts teachers would be in shock. Some might believe Harry is right, especially those who have always been a bit suspicious of Snape, while others would be outraged and demand an explanation from Harry.
The Slytherin students would be the most vocal in their opposition to Snape's arrest. They see Snape as one of their own, a protector of their house. They would likely start rumors and spread discontent about Harry throughout the school. Some might even try to take revenge on Harry for what he's done. Meanwhile, the students in Gryffindor would be divided. Some would support Harry wholeheartedly, while others would be hesitant, waiting to see how the situation unfolds.
Hermione would probably be shocked at first. She is a rational person, and this goes against the normal relationship dynamics she is used to. But then she might try to understand it from a logical perspective, thinking about how their relationship has developed over time. Ron, on the other hand, would likely be more vocal in his disbelief and might even make some jokes about it at first.
Maybe Harry accidentally frames Weasley for something. It could be due to a misunderstanding, like a spell gone wrong that makes it seem like Weasley was involved in some illegal magic use.
The Glee club members would be shocked. Rachel, for example, would probably be very vocal about her disbelief and start campaigning for Finn's release. She might even organize a benefit concert to raise money for his legal defense.
In the fanfic, it could be that Snape is caught in a political struggle within the wizarding world. Harry, who is on the side of the 'good' political faction, uncovers Snape's involvement in some underhanded schemes for the opposing side. As a result, he has no choice but to get Snape arrested to protect the safety and stability of the wizarding community.
At first, Harry is likely to be angry. He might feel that Snape is being unfair and targeting him. Harry has a strong sense of justice, and when he believes he's being wrongly punished, he'll be resentful.
Maybe it's a corrupt Ministry of Magic official. They might use Harry's credibility to their advantage and trick him into providing false information about Weasley. They could be after the Weasley family for political reasons or because they want to cover up their own misdeeds by creating a distraction with Weasley's arrest.
Snape could be initially shocked. He's used to seeing Harry as a rather tough and rebellious student. So, seeing Harry cry might take him aback for a moment. Then he might become a bit more guarded and try to figure out if Harry is faking it or not.
Harry would probably be extremely embarrassed at first. He might blush furiously and stutter out an apology. Snape, on the other hand, would be shocked and likely try to hide his own confusion. He might initially be angry, thinking it was some sort of prank, but then as he realizes Harry's genuine emotion, he would be at a loss for words.
In the fanfic, Harry could have a range of reactions. At first, he might be in denial, thinking that Hermione is just joking or that she will change her mind. Then, when he realizes it's for real, he could get angry, feeling like he's been unfairly judged or rejected. However, over time, he may come to accept it and focus on other aspects of his life, like his fight against the dark forces or his relationships with other friends.
At first, Harry would be confused. He has always seen Snape as a complex figure, and the idea of being rejected as a son would be a shock. He might start to question his own self - worth, thinking that if Snape doesn't want him, there must be something wrong with him. As time passes, he could grow bitter towards Snape, but also use this as motivation to become stronger. He might focus on his friends and the positive relationships in his life, trying to move on from Snape's rejection while still carrying the pain deep inside.