It could be Orochimaru. He might see the baby versions of Team 7 as perfect subjects for his experiments. He could try to kidnap them to use their unique chakra or potential for his own dark purposes.
Maybe in the fanfiction, an enemy uses a jutsu to turn Team 7 into babies. Kakashi then has to figure out how to reverse the jutsu while dealing with the cute but sometimes troublesome baby versions of his students. For example, Naruto might be constantly hungry and crying for ramen, Sasuke could be moody and brooding even as a baby, and Sakura might be overly energetic and trying to 'help' Kakashi in her own clumsy way.
Kakashi is often a favorite. His cool and mysterious demeanor, along with his powerful jutsu, make him a central and exciting character in fanfiction. He has a lot of room for backstory exploration.
Well, if Team Minato meets Team Kakashi in a fanfiction, it could lead to some epic battles or friendly competitions. Maybe they would have a sparring match to see which team is stronger. Team Minato with their speed and unique jutsus, and Team Kakashi with their diverse skills. Or they could collaborate on a mission, with Minato's leadership guiding both teams. It would be exciting to see how the different personalities interact, like Obito from Team Minato and Kakashi from Team Kakashi. They have a complex history that could be explored further in such a meeting.
One possible replacement could be Gai. He is a strong and enthusiastic ninja who has a friendly rivalry with Kakashi. He could bring a different kind of training style to Team 7, focusing more on physical and direct combat training, which would contrast with Kakashi's more laid - back and strategic approach.
At first, Kakashi might try to distance himself from Team 7's possessiveness. He values his independence and doesn't want to feel smothered. However, as he realizes that their actions are coming from a place of deep love and loyalty, he starts to accept it more. He may even start to rely on them a little bit, for example, allowing them to help him with his paperwork or other small tasks that he usually does alone. This shows a new level of trust and closeness between them.
Kakashi would approach Naruto's pranks with a mix of discipline and love. For instance, if Naruto tries to scribble on the walls, Kakashi would stop him gently. He'd then sit Naruto down and show him where he can draw instead, like on a piece of paper. He'd also tell Naruto stories about how important it is to respect their home. When Naruto does something really naughty, like trying to pull the cat's tail, Kakashi would firmly say 'No' but then immediately follow it up with a hug. He wants Naruto to learn right from wrong but also wants to make sure Naruto knows he is loved no matter what.
Probably Naruto. Since Minato is his father, he has always longed to know more about him. Meeting Minato and his team would be a dream come true for Naruto. He would be eager to hear stories from his father's past, about his training, and how he became such a great ninja. Naruto might also want to show off his own skills to his father and the rest of Team Minato.
Maybe. If the fanfiction stays true to Kakashi's character in their eyes, they might approve. For example, if it shows his loyalty and skill, they could be okay with it.
The concept is popular because it allows fans to fill in the gaps in the original story. The anime and manga may not fully explore all aspects of Kakashi's feelings for Team 7. Fanfiction gives the opportunity to go deeper into their relationships. For example, how does Kakashi really feel when Sasuke leaves the village? What does he do behind the scenes to support Naruto's growth? These are the kinds of things that fans love to write about and read in fanfiction.