Snape would likely have a very critical view. Given his sharp intellect and his own deep understanding of the wizarding world and the characters in it. If he reads the epilogue fanfiction, he might scoff at any inaccuracies or misinterpretations of the characters' personalities. He could also be a bit sad, thinking about how things could have been different for him in the future depicted in the fanfiction.
Well, Snape would first be extremely confused as to what this 'fanfiction' thing even is. But once he starts reading the epilogue fanfiction, he'd be intrigued yet appalled. He might find it fascinating that people are imagining the future of the wizarding world he was a part of, but at the same time, he may not like the liberties taken with the characters. For example, if his own character is not depicted in a way he thinks is accurate. He may also feel a sense of detachment, as this is a world created by fans, not the real wizarding world he knew.
He might be quite amused. Dumbledore has a great sense of humor and an open mind. He would probably find the creative interpretations of his world and the characters he knows so well to be an interesting study of how others perceive Hogwarts and its inhabitants.
He might be really surprised. Some fanfictions could have really out - of - the - box ideas that he'd never thought of. For example, if there's a fanfiction about him having a different kind of training with a new teacher, he'd be like 'Whoa, that's a new take on things.'
He might be amused. Tony Stark has a big ego and seeing how fans imagine his adventures in fanfictions could be quite entertaining for him. He'd probably chuckle at some of the wilder ideas and might even be flattered by the creativity of his fans.
He might be amused. Percy has his own set of adventures, but reading about Magnus' would probably make him chuckle at the different takes on Norse mythology in the fanfiction.
Percy could find it both strange and fascinating. Since he has his own set of adventures and challenges, reading about Harry Potter's world through fanfiction might make him think about how different yet similar their situations are. He might be amused by some of the out - of - the - box ideas in the fanfiction.
He might be quite surprised. The fanfiction could present alternative versions of the characters' futures that are very different from what he experienced. It could make him reflect on his own life and the events that led to the epilogue in the original story.
He would probably be very displeased. Snape has always been strict and traditional, and fanfiction about the DA, which was an unauthorized student group in his eyes, would seem like a frivolous and inappropriate thing to him.
He might be quite surprised. Fanfiction often takes the original story in new and unexpected directions. He could be intrigued by different interpretations of his own character or the events at Hogwarts.
He'd probably be in awe. Just imagining his dad with all that power would be mind - blowing for him.
He would probably be furious. The blood quill was a very cruel and unjust tool used on him as a student. Discovering fanfiction about it might make him feel that his past pain is being exploited or made light of.