Orochimaru's experiments and his knowledge of forbidden jutsu would be far ahead of the time he travels back to. He could use this to his advantage, perhaps by creating new techniques based on the limited knowledge of the past. However, he also has to be careful not to change the future too much as his actions in the past could have unforeseen consequences for his future self.
Also, in the past, they might have to adapt their fighting styles. Naruto, used to fighting with his friends and allies from his own time, now has to work with different ninja in the past. He may have to learn new teamwork strategies and combine his abilities with those of the past - time ninja in a different way. Tsunade might also have to rely more on her brute strength and less on her developed medical and strategic skills from the future, at least until she can adjust to the past situation.
When the Konoha 12 time - travel to the past, their abilities would change significantly. Take Rock Lee for example. In the past, there might be different training methods that could further boost his physical strength and taijutsu skills. He could learn from the masters of old and bring back new techniques. For Ino, her mind - transfer jutsu might work differently in the past due to the different mental states and chakra signatures of the people then. And for Shikamaru, his strategic thinking would have to adapt to the different political and combat situations of the past. Their abilities would not only change in terms of power but also in how they are applied in the context of the past's ninja world.
Well, in the past, Naruto's ability to use Sage Mode might change significantly. In his own time, he has a certain way of gathering natural energy. But in the past, the distribution of natural energy could be different. He might have to learn a new method from the Sage of Six Paths himself. Also, his Rasengan could be improved. He could combine it with ancient jutsu knowledge from that era, creating a more powerful and unique version of the Rasengan. And his social abilities, like his knack for making friends and uniting people, would also play a big role. He could use these to gain allies in the past, which in turn could help him develop his abilities further as he would have more resources and knowledge at his disposal.
In the past, Team RWBY's abilities could change in various ways. Ruby's semblance of speed would give her an edge in battles, but she might also attract unwanted attention as people in the past may not be used to such swift movements. Weiss's Glyphs could potentially be more powerful in the past if the Dust in that era has different properties. Blake's ability to create clones could be misinterpreted as some kind of dark magic, causing her to have to be more careful about using it. Yang's power might be more difficult to control as the technology to understand and manage it might not exist, making her a bit of a loose cannon in the past.
Sasuke's abilities would be both advanced and out of place. His Sharingan skills would be very powerful compared to most in the Sannin era. But he would lack some of the basic knowledge and skills that were common in that time. For example, he might not be as well - versed in some of the traditional ninjutsu styles.
The combination of Naruto and Madara's abilities would bring about a significant shift in the power balance of the world they time travel to. Naruto's positive influence and ability to inspire others, combined with Madara's strategic mind and combat skills, could lead to a new era of peace and cooperation. Their combined ninjutsu could also revolutionize the way ninjas in that time train and fight. For instance, Naruto's Rasengan combined with Madara's fire - based jutsu could create a whole new type of attack that others would try to emulate.
His personality could also become more calculating. Since the Sannin were known for their strategic thinking, Naruto would start to think several steps ahead. He might be more secretive about his plans too. He would no longer be the open - book Naruto. Instead, he would be like Jiraiya, who had his own secrets and plans. He would also show more patience, which is something he lacked before but the Sannin had in abundance when dealing with complex situations.
Well, their relationship would likely become more confident. Since they are already married, Hinata wouldn't be as shy around Naruto as she was in the original timeline. Naruto would also be more aware of Hinata's feelings and his own for her. He would probably be more protective of her right from the start.
Kakashi's abilities would likely be enhanced in the past. He has all the knowledge and skills he's gained in the future. So, his combat skills would be more refined. His Sharingan would be even more powerful as he would know better how to use it. He might also be able to teach his younger self some new jutsu that he learned over the years.
His relationships would be quite different. With Sasuke, he might be more of a mentor - like figure early on, as he'd have more knowledge and power from the Sannin's teachings. His relationship with Sakura could be more of an equal partnership in combat, since he'd have more medical knowledge from Tsunade. And with Kakashi, he'd probably still respect him, but he'd also have his own unique insights from the Sannin that could make their interactions more like exchanges between equals.