Well, if Konoha 12 watches the future 7th Naruto in fanfiction, they would probably have mixed reactions. Some, like Shikamaru, might immediately start thinking about the implications of Naruto's future actions on the present. Others, like Kiba, might be more excited to see Naruto's new jutsu or how he has become even stronger. And Sakura might be emotional, seeing how Naruto achieved his dream and how much he has changed from the boy she once knew.
Obviously, characters from Konoha will be central. Naruto might be one of the main characters as he often represents the heart of Konoha. His ability to change things could be key in how Konoha responds to the future it sees.
It could be developed by having them see different possible futures depending on their choices. For example, if Naruto decides to pursue a different path in training, they might see a future where Konoha is in more danger or where peace is achieved more quickly.
Well, one interesting plot point could be how Konoha's perception of the future changes its current actions. Maybe it sees a great threat coming and starts to train its shinobi in new ways.
The Konoha 12 would likely be in shock. They've seen Naruto grow, but this fight against Pain is on a whole new level. Some, like Shikamaru, would immediately start analyzing the battle strategies. Sakura might be worried sick about Naruto's safety, while Kiba could be cheering Naruto on loudly, impressed by his power.
He might get some insights into different possible futures for himself and his friends. It could be both inspiring and a bit disconcerting as he sees versions of events that may or may not come to pass.
Their view would likely change to one of even greater respect. They already respected Naruto for his tenacity and strength, but seeing him as Hokage would show them the full extent of his growth and leadership.
In such a fanfiction, one possible scenario could be that Naruto sacrifices himself to save Konoha from an ultimate evil. Maybe a powerful enemy like Kaguya returns in a more menacing form and Naruto, seeing no other way, uses all his power and gives his life to seal the threat away.
One of the most dramatic moments could be when Naruto first takes a really hard hit from Pain. The Konoha 12 would gasp in horror, and Sakura might even try to run out to help. Another moment could be when Naruto taps into a new level of power. The expressions of shock and awe on the Konoha 12's faces would be quite something.
I'm not sure specifically as I haven't read it. But it might be about the 78th class observing or experiencing events in a future - perhaps their own future, or the future of the world they are in. It could involve adventures, changes in their relationships, or new challenges they face in that future setting.