They might be quite surprised. Minato could be amused to see different interpretations of his heroic deeds. Kushina might be a bit shocked at some of the wild ideas about their family or Naruto. For example, she might not expect some of the out - of - character scenarios written in the fanfiction.
Minato, being a calm and collected person, would likely take reading Naruto fanfiction as an interesting pastime. He could be intrigued by the creativity of the fans. Kushina, with her fiery personality, might have a more emotional reaction. She could be either very excited to see the love fans have for Naruto through their fanfictions or angry if she felt the fanfictions were disrespectful to their family. For instance, if a fanfiction made Naruto seem weak when she knew how strong he truly was, she would not be happy.
Minato and Kushina's reactions could be complex. Minato, as a former Hokage, might initially be a bit cautious about how the fanfiction portrays the ninja world and its values. However, he would soon appreciate the new perspectives. Kushina would be thrilled from the start. She would be eager to explore the various relationships that Naruto has in these fan - created stories. She might also be amused by some of the more out - there plotlines, like Naruto having some extraordinary new powers that she hadn't thought of. And both of them would probably feel a sense of connection to the fans through these fanfictions.
They might be quite surprised. Minato might be proud to see how much Kakashi has grown in the fanfiction and how he is still upholding the values Minato instilled in him. Kushina could be amused at the creative interpretations of Kakashi's character. Maybe she would also feel a bit of motherly pride seeing how Kakashi has become an important figure in the village in these fictional stories.
One possible reason could be a misunderstanding. Maybe Minato thought Kushina had done something to endanger Naruto when in fact she hadn't. In the heat of the moment, he lost his temper and slapped her.
In a fanfiction, if Minato were to slap Kushina, it would be a huge shock to the Naruto - Kushina relationship. It could potentially cause a rift between Naruto and his father Minato in Naruto's mind. Also, Kushina would likely be deeply hurt and angry, which might lead to her distancing herself from Minato. This event could also change the way Naruto views his family's past and his parents' relationship.
Maybe out of curiosity. They want to see how the fans view Kakashi, who was an important part of their lives. Kakashi was Minato's student and Kushina knew him well too. So they are interested in the different perspectives presented in the fanfiction.
The implications would be huge. It would completely shatter the positive family image that the Naruto series usually portrays. Fans who love the relationship between Naruto and his parents would be very shocked and possibly offended.
Well, in such a fanfiction scenario, Minato and Kushina reading the future would be a game - changer. They may use the knowledge to prevent the Nine - Tails attack on the village. They could also influence Naruto's upbringing in a more direct way. They might see the rise of new enemies and start training the next generation earlier to combat those threats. This would completely rewrite the Naruto story in many ways.
On a more personal level, they could face internal guilt. As Naruto grows up and achieves great things on his own despite their neglect, Minato and Kushina may realize what they've missed out on. This realization could cause them a great deal of internal turmoil and regret for not being there for their son when he needed them.
Minato would probably be very proud. He might notice Naruto's use of his own jutsu and be impressed by how Naruto has developed his skills. Kushina would be more emotional, maybe crying at the sight of Naruto growing up so well.
It would be very controversial. Fans of the original Naruto series who love the pure and loving relationship between Kushina and Minato would be extremely disappointed. It could also create a lot of negative buzz in the Naruto fan community as it goes against the established characters' personalities.