Well, Mikey might be a bit surprised at first. He would probably be intrigued by the different scenarios the fanfiction presents about Takemichi. Draken, on the other hand, might be more critical and analyze how the fanfiction portrays Takemichi's growth and relationships. Mitsuya could find it interesting from an artistic point of view, seeing how the writer has used Takemichi's character to create new stories.
Some characters might become more protective of Takemichi if the fanfiction shows him in a difficult situation. They would feel a stronger bond towards him, wanting to ensure his safety. However, if the fanfiction distorts Takemichi's character too much, it could cause some confusion and even a bit of a rift. They might start to question if they really know Takemichi as well as they thought.
One interesting fanfiction could be one where Sakura Haruno somehow gets transported into the Tokyo Ghoul world. In this story, she might use her medical skills from Naruto to help the ghouls with their unique biological needs. Maybe she teams up with Kaneki to find a way to co - exist between humans and ghouls in a more peaceful way.