Some would be in shock and disbelief. People who idolized Dumbledore would initially refuse to believe Harry's claims. They would think Harry was either misinformed or had some malicious intent.
There would be shock and disbelief. The wizarding world has always seen Hogwarts as a symbol of hope, knowledge and safety. If Harry destroys it, many would be in denial at first, thinking it couldn't be true. Wizards and witches from all over would come to the ruins, trying to figure out what had happened.
The Ministry of Magic would probably be in an uproar. They might see Dumbledore's actions as a blatant abuse of power. They would send out Aurors to search for Harry and arrest Dumbledore. After all, Dumbledore is one of the most powerful wizards, and his actions would be seen as a threat to the stability of the wizarding world.
The wizarding world in the fanfiction might be in chaos. People who idolized Dumbledore would be shocked and perhaps feel betrayed. There could be a lot of gossip and rumors flying around. Some might even start to question other things Dumbledore has done in the past.
Maybe Harry uncovers evidence that Dumbledore had been manipulating him all along. Like Dumbledore knew more about Voldemort's connection to Harry than he let on, and he was using Harry as a pawn in a bigger game. Harry, feeling betrayed, decides to expose Dumbledore's true nature, which would shatter the positive image everyone had of him.
Some might be angry, thinking he's abandoning his responsibilities. The Ministry of Magic might try to persuade him to come back or even use force if they thought it was necessary for the safety of the wizarding world. His friends, on the other hand, would likely be sad and try to understand his reasons. They might also try to convince him to return, as they know how much he means to the fight against evil in the wizarding world.
Some in the wizarding world would be excited. The French wizarding community might see it as a great connection to the famous Harry Potter from Britain. They would celebrate the union as a way to strengthen the relationship between the two magical communities. However, there might also be some who are skeptical. Some traditional British families might think it's a bit odd as they don't know much about Apolline. But overall, most of Harry's friends would be happy for him and look forward to the new cultural exchanges that would come with the marriage.
They would be devastated. Harry has many friends and allies. People like Hermione and Ron would be heartbroken and would probably seek revenge. The Hogwarts faculty would also be deeply affected. Dumbledore, if he's still alive in the fanfiction, would feel a great sense of guilt for not protecting Harry better. There might be a split in the wizarding community, some believing the Dursleys were acting on their own, others suspecting a darker conspiracy.
There would be a great deal of shock and confusion. Many would start to question everything they had believed in. Families would be divided. Some might think that Harry had been corrupted by Voldemort's dark magic and try to find a way to reverse it. The Ministry of Magic would be in a panic. They would try to come up with new strategies to deal with this new threat. Teachers at Hogwarts would be worried about the safety of their students. And the Death Eaters, while initially happy to have Harry on their side, would also be suspicious of his motives and loyalty.
The wizarding world would likely be in shock. Harry is seen as a symbol of hope against Voldemort. His death at the hands of Vernon would be a huge blow. There would probably be a lot of anger towards the non - magical world for allowing such a thing to happen.
The wizarding world would be in shock. Harry is seen as a hero, and for him to kill Draco, even if Draco was from a 'less popular' side, would be a huge scandal. His friends like Hermione and Ron would be deeply conflicted. They would be torn between their loyalty to Harry and their disbelief at his actions.