Some characters might be critical. Elsa, being a powerful and responsible character, might not like it if the fanfiction misrepresents her in a way that goes against her values. She might think that the writers should be more respectful of her character arc and not make her do things that are completely out of character just for the sake of a wild story. However, at the same time, she might also appreciate the creativity in some parts.
Some would be intrigued. Captain America, being an open - minded person, might be interested in seeing different interpretations of their team dynamics. He could even gain new insights about his relationships with his fellow Avengers through the fanfiction.
Some might laugh. They could find the humorous takes in the fanfiction really entertaining. Maybe there are some comical interpretations of their actions or dialogues that they themselves didn't expect.
Some characters might be shocked. They may not expect such wild interpretations of their lives and relationships.
Naruto would be thrilled. He loves being the center of attention and seeing all these stories about him would make him feel even more important. He'd probably want to meet the writers and tell them how cool he thinks their ideas are.
Some characters might laugh. They would see the humorous side of how fans have twisted and turned their stories. It could be like seeing a new, comical version of their own lives as depicted in the musical.
They could have a range of reactions. Naruto would likely be excited and eager to see new stories about his world. He loves adventures and would be interested in seeing different takes on his life.
Elsa would be extremely worried and angry. She would probably use her powers without hesitation to find Anna. Kristoff would be very determined to rescue Anna. He loves her and would do anything to get her back. Olaf might not fully understand the situation at first but would still try to help, like using his cheerfulness to keep Anna's spirits up while she's kidnapped.
Some characters might be excited. They could be interested in seeing how their story continues in the fanfiction. Others might be skeptical and think that the fanfiction is not a true representation of their possible futures.
Some characters might be very interested and engaged. They could get drawn into the new stories and ideas presented in the fanfiction.
They may laugh. If the fanfiction contains some humorous scenarios or dialogues that are well - written. For instance, if there are some comical interactions between the dragons and the riders that are different from what's in the movie.