If Naruto was trained by Danzo and joined Team 7 in a fanfic, his abilities would change significantly. Danzo's training would probably give him a more strategic mindset. He could be more proficient in using weapons and stealth. In Team 7, he'd learn to coordinate with Sasuke and Sakura. His chakra control might improve in different ways, and he could develop new jutsu that are a combination of what he learned from Danzo and what he discovers while on missions with Team 7.
Naruto's abilities would be a mix of the old and the new. Danzo's training would introduce him to darker and more covert skills. He might be able to move more quietly and strike more lethally. In Team 7, he'd have to adapt those skills to the more open - minded and team - based approach. His Rasengan could potentially be modified with some of the techniques he learned from Danzo. His physical strength might be enhanced in different ways, and his ability to sense danger and opponents could be sharpened. He'd also be better at using the environment to his advantage, which is something Danzo would have emphasized in his training.
Well, if Naruto was trained by Danzo, he might be more ruthless at first. But joining Team 7 could soften him up. He'd probably bring some of Danzo's combat techniques and secrecy to the team. It could make for an interesting dynamic, with Naruto being a bit more of an enigma compared to his canon self.
His combat abilities would become more diverse. Madara could teach him new forms of taijutsu and ninjutsu. For example, Naruto might learn some of Madara's signature space - time ninjutsu, which would give him an edge in battles. His chakra control would also improve as Madara is very proficient in chakra manipulation.
His abilities would be enhanced greatly. He could have better chakra control. For instance, he could use chakra more efficiently and might be able to perform jutsu with less effort. His physical abilities like strength, speed and agility would also improve. He could run faster than normal ninjas and jump higher.
If trained by Sanji, Naruto's sensory abilities could get better. Sanji has a good sense of smell which he uses in various situations. Naruto could learn to use his senses more effectively, not just relying on his chakra senses. Also, Naruto's ability to endure pain might increase. Sanji has endured a lot in his life, and he could pass on some of that mental toughness to Naruto, allowing him to push through tougher battles and train harder without getting worn out as easily.
Naruto's abilities would change significantly. Ichigo has unique spiritual powers, and through his training, Naruto might develop a form of 'spiritual chakra'. His ninjutsu could become more powerful as he combines the new understanding of energy with his existing chakra control. Also, Naruto's combat strategy would shift as he learns from Ichigo's more direct and aggressive fighting style.
Naruto would probably develop a more diverse set of combat skills. With Edward's training, he could incorporate more acrobatic maneuvers into his fighting style, similar to how Edward moves on ships and during battles. His perception skills would also be sharpened as he learns to read the intentions of his opponents in different ways. For example, instead of relying solely on his ninja senses, he could learn to read body language like a pirate. His ability to adapt to new environments would be enhanced as well, since Edward has experience in various terrains and situations.
He might become more cautious. Tsunade is a more calculating ninja compared to some of Naruto's previous mentors. So Naruto could start to think before he leaps, rather than just charging into battle head - first all the time.
Naruto's relationship with his sensei, like Kakashi, would change. Kakashi would be both proud and cautious. Proud because Naruto is getting stronger, but cautious as the Shinigami - related training is uncharted territory. His bond with the other villagers would also shift. Some might see him as a protector with new, otherworldly powers, while others might be suspicious of the Shinigami's influence on him. Overall, his relationships would be in a state of flux as he adapts to his new self after the training.
His relationship with Sasuke might be affected. Naruto might approach Sasuke differently, with new strategies learned from Zetsu. He could be more secretive about his intentions towards Sasuke, which might either make Sasuke more curious or more distrustful. With his friends in Konoha, they might be a bit wary of Naruto at first because of his new training source. But once they see that Naruto is still on their side, they would support him.
His speed would increase a great deal. Whis is very fast and could teach Naruto how to move more swiftly. Also, Naruto's chakra control might be enhanced, allowing him to perform more complex jutsus with less effort.