Surprisingly, Sasuke could end up being a support for Naruto in this situation. They have a complex relationship, but both have known what it's like to be alone and ostracized in Konoha in different ways. Sasuke may understand Naruto's pain and they could end up working together to face the world that has been cruel to them both.
Jiraiya could be one to support Naruto. Jiraiya has a connection with Naruto already, and he's the type who goes against the norm. He would likely take Naruto under his wing and help him grow in strength and confidence away from Konoha.
Sasuke could be one of the characters to support Naruto. They have a deep bond, and Sasuke might understand Naruto's reasons for wanting to change Konoha. Also, Shikamaru, being a smart strategist, might see the potential in Naruto's plan and choose to support him.
Sasuke could be one of the characters to support Naruto. Given their complex relationship and Sasuke's own issues with Konoha in the past, he might see Naruto's cause as just. Another one could be Jiraiya. If he were alive and found out about the real reasons behind Naruto's revenge, he might side with Naruto as he always cared for him deeply. Also, some of the outcast ninja within Konoha, like those who have been discriminated against because of their bloodline or lack of skills, might support Naruto as they also have grudges against the village system.
Shikamaru might be sent to find Naruto. He's known for his intelligence and strategic thinking. The village elders might trust him to be able to track Naruto down and either convince him to come back or at least find out his intentions. Shikamaru also has a certain respect for Naruto and would understand his motives to some extent.
Maybe some of the more conservative village elders. They have always been a bit wary of Naruto because of the Nine - Tails inside him. So they might be behind his capture in the fanfiction.
Perhaps the Konoha leadership made a bad decision. They might have thought that distancing themselves from Naruto would be better for the village's overall image. Or they were influenced by some elders who held grudges against Naruto's father and took it out on Naruto.
Well, he could encounter new allies and enemies in different villages and face all kinds of challenges on his own journey.
Konoha would most likely send out a search and rescue team immediately. This team would likely consist of some of their strongest ninja. For example, Kakashi might be sent as he has experience dealing with dangerous situations and is very skilled. They would also try to gather intelligence on where Naruto was taken in Iwa.
Sakura could be one of the main characters. She has a long - standing relationship with Naruto and might play a role in convincing him to return. Maybe she tells him about the state of the village's hospital or how his friends miss him.
Naruto also finds solace in his dreams of becoming Hokage. He believes that if he becomes the most powerful and respected person in the village, people will finally accept him. He uses this goal as a driving force to keep going despite the abandonment. He trains hard and tries to improve himself constantly.
A new character could be introduced as the main antagonist. Maybe a powerful ninja from another village who has infiltrated Konoha's politics. This character could be the one behind the idea of forcing Naruto back, with the intention of using Naruto as a pawn in a larger scheme against Konoha.