Well, it could be that Naruto has changed a great deal during his time away from Team Seven. When they meet at Wave, there might be some initial tension as they adjust to the new Naruto. But soon they would likely fall back into their old dynamic, with Sasuke being his usual brooding self, Sakura being concerned for Naruto, and Kakashi just being laid - back and guiding them. They might also discover some new mysteries about Wave that they need to solve together.
Their relationships could become stronger. Naruto's presence might bring new energy to the team. Sasuke might start to respect Naruto more, and Sakura would be happy to have the team back together.
There could be a fanfiction where Team Seven is brainwashed or under some sort of mind control. As a result, they turn on Naruto and attack him. This would be extremely hurtful to Naruto, both physically and mentally. He would be confused as to why his friends are suddenly trying to harm him and it would shatter his trust in them.
One possible reason could be a sense of being undervalued. Maybe he felt that his teammates didn't fully appreciate his efforts during the Wave mission. For example, if Sasuke got most of the credit, Naruto might feel pushed aside.
The interactions would be full of curiosity. Naruto would be eager to know how Kakashi became so strong at a young age. Sasuke would be sizing Kakashi up, looking for ways to improve his own skills. Sakura might be a bit shy at first but then start chatting with Kakashi about his life. Kakashi, on the other hand, would be a bit cautious yet intrigued by Team Seven.
Well, one possibility is that Naruto would be super excited. He might start asking Young Kakashi all sorts of questions about his jutsu and training. Sasuke would probably be more reserved but still interested in Kakashi's skills. Sakura could be fangirling a bit, seeing the young and talented Kakashi. They might end up learning some new techniques from him or getting involved in an adventure together.
In some fanfictions, Naruto might be depicted as hating Team Seven due to a miscommunication. For example, if Sasuke is written as constantly undermining Naruto within the team and Sakura always takes Sasuke's side, it could lead to Naruto feeling isolated and developing negative feelings towards the team.
The dynamic between the characters would be completely different. Without Naruto, Sasuke would lack his main rival within the team. Their growth as characters might be stunted as they wouldn't have that constant push from Naruto. Also, Sakura would be missing an important friend and source of motivation.
I think there would be a mix of emotions. Naruto would feel a connection right away, but the younger Team 7 might be a bit confused. They might not understand why this older Naruto is so interested in them. But as time goes on, they would start to trust him. Naruto could play games with them to break the ice, like ninja tag or something. And he would be constantly trying to boost their confidence, especially Sasuke who has a lot of pride.
Well, one possibility is that future Naruto has some sort of warning about a great danger that is coming to their present time. So, he travels back to meet Team 7 to prepare them. Team 7 would then have to deal with the knowledge that they are somehow crucial in preventing this future threat. And of course, there would be a lot of emotional moments as they see what Naruto has become.