A plot twist could be that when Naruto adopts Kakashi, it's actually a ruse to protect Kakashi from some secret organization. Naruto pretends to be Kakashi's adoptive father while they secretly work together to uncover the secrets of this organization. Along the way, they face many challenges and their relationship deepens.
Maybe Naruto adopts Kakashi in a post - war scenario where Kakashi has lost his purpose. Naruto, seeing Kakashi's lost state, decides to take him under his wing. As a result, Kakashi starts to learn new jutsus from Naruto and they develop a bond that is more like brothers. This would be a great opportunity to explore their characters in a different dynamic.
One possible plot twist could be that Anko has a hidden power that Naruto uncovers during the adoption process. Maybe she has a connection to an ancient clan or a special jutsu that she's been suppressing. This discovery could change Naruto's view of her and also put them in danger as others might be after that power.
One possible plot twist could be that Naruto actually steals something from Kakashi that he thought was unimportant, but it turns out to be a key to a hidden jutsu or a secret mission. Another could be that Kakashi knew Naruto was going to pickpocket him all along and let it happen as part of a training exercise. Maybe Naruto pickpockets Kakashi, but then realizes he has to return the item quickly because it's something that Kakashi needs to save the village.
One possible plotline could be Kakashi teaching them unique ninja skills. Since he has his own set of diverse abilities, he could pass on some of his more unorthodox techniques to Naruto, Sasuke, and Sakura. For example, he might teach Naruto a more refined version of the Rasengan, or help Sasuke better control his Sharingan powers. And for Sakura, he could train her in some of his stealth and assassination techniques, which would add a new dimension to her combat skills. Another plotline could involve Kakashi helping them deal with their personal issues. He could be a mentor figure for Naruto in understanding his loneliness and the importance of his role as a Jinchuriki. For Sasuke, Kakashi could play a key role in his journey to avenge his clan while also guiding him to not be consumed by hatred. And for Sakura, he could assist her in growing more confident in her abilities and not being overshadowed by her teammates.
One possible storyline could be that Kakashi and Anko notice Naruto's loneliness and decide to take him in. They start by teaching him more advanced ninja skills. Kakashi might focus on his Sharingan techniques, while Anko could teach him some of her unique snake - related jutsu. With their combined efforts, Naruto could grow into a more powerful and confident ninja at a faster pace.
One possible plot twist could be that they face opposition from the Hidden Leaf Village. Since same - sex relationships might not be as openly accepted in the traditional ninja world. Another twist could be that they have to go on a dangerous mission together right after getting married, which tests their new relationship. And perhaps there's a secret enemy who wants to break them apart because their union represents a new kind of hope in the village.
One possible plot twist could be that they discover their brotherhood in a very unexpected way. For example, during a dangerous mission, Kakashi might get severely injured and in a moment of delirium, he reveals a long - hidden memory that points to their relation. Naruto, being shocked at first, then realizes it explains some of the strange feelings of connection he had towards Kakashi all along.
One possible plot twist could be that Sakura has to face opposition from the village elders. They might be skeptical of her ability to raise Naruto, given his status as a jinchuriki. Another twist could be that Naruto starts to show signs of his powerful chakra at a very young age, which makes it difficult for Sakura to control the situation.
A really interesting plot twist could be that female Naruto is actually from an alternate dimension where she and Kakashi are already married. In this new world, things are different, and she has to figure out how to make their relationship work in this dimension too. Plus, there could be a character who is jealous of their union and tries to break them apart by spreading false rumors about Kakashi's past, which female Naruto has to deal with.
One possible plot twist could be that their relationship is initially opposed by the village elders. They might see it as unconventional or worry about how it could affect Naruto's role as a potential Hokage. Another twist could be that an old enemy resurfaces and targets Kakashi to get to Naruto, seeing their marriage as a weakness to exploit.
Perhaps a really cool plot twist is that the time travel was actually a trap set by an old enemy. When Kakashi and Naruto travel back, they find out that this enemy has been manipulating events from the past all along. They then have to not only fix the past but also figure out a way to stop this enemy from using the past to destroy their future.