Well, one antagonist could be Sasuke. If he goes down a dark path again, his actions could cause Naruto great pain. Minato would then watch as Naruto tries to deal with his best friend's betrayal or attacks. Zetsu is also a potential antagonist. He has his own hidden agendas and could be manipulating events behind the scenes to make Naruto suffer. And there are always the hidden threats within the shinobi world, like certain hidden village leaders who might see Naruto as a threat and try to harm him, with Minato observing all this.
Well, it depends on the specific fanfic. Some fanfics might really emphasize Naruto's growth to be on par with Minato in terms of smarts. They could show Naruto learning from Minato's memories or having some sort of spiritual connection that transfers knowledge. However, other fanfics might focus more on other aspects of Naruto's character and not necessarily make him as smart as Minato.
They would be empathetic. Minato, as Naruto's father, would especially feel a deep sense of pain seeing his son struggle. He would want to reach out and comfort Naruto during his lonely times when the village shunned him because of the Nine - Tails.
There are many out there. A really good one might focus on the emotional reactions of Team Minato. For example, Minato might be proud of Naruto's strength and how he overcomes Pain. Kakashi could be in awe at Naruto's new techniques. Their reactions can enhance the overall viewing experience in the fanfiction.
One possible theme could be regret. Minato might feel regret for not being there to protect Naruto, which adds to the emotional turmoil as he watches his son suffer. Another theme could be the cycle of pain. Naruto's suffering might be seen as part of a larger cycle that Minato was unable to break. Also, there could be a theme of growth through adversity. Even though Minato is just watching, Naruto's suffering could lead to his growth as a character, and Minato might witness this transformation.
Kushina could be an important character even though she's dead in the original story. In this fanfic, her spirit or memories could play a role in Naruto's upbringing. For example, Minato could tell Naruto stories about Kushina's feisty personality and her love for the village.
There's a fanfic called 'Minato's Return'. In this story, Minato somehow returns and gets to see Naruto's growth. It's really interesting to see how he interacts with Kushina, who is also there in the story, and how they both guide Naruto in new ways. The descriptions of their family bond are heartwarming.
I'm afraid I'm not aware of any particular fanfic with this exact premise that I could recommend. However, when you search on fanfic platforms, read the reviews and summaries carefully. Some fanfics might have a similar concept but not the exact same title. Maybe look for ones that explore alternate universes or dark timelines in the Naruto world.
Yes, there might be such fanfics in the vast Naruto fanfic community. Some fanfic writers like to create alternative scenarios where the characters' identities are swapped or unexpected events like the main character's death occur. These fanfics often explore different aspects of the Naruto universe and the characters within it.
Well, Naruto has had the advantage of learning from many great shinobi over time. He also has a unique bond with his friends which could potentially give him more strength. Minato, on the other hand, had a shorter lifespan to develop his powers. Naruto has had more time to grow and surpass his father in strength.