Definitely Sasuke. Their bond is such that Sasuke would not stand by and let Naruto destroy Konoha. He has his own reasons to protect the village now. Shikamaru is also a likely candidate. He's intelligent and would quickly figure out that Naruto's actions are wrong. He would use his strategic mind to try and stop Naruto. And Hinata, who loves Naruto deeply, would oppose him in the hopes of bringing him back to his senses.
Sasuke would be at the forefront. He has a history with Naruto and a newfound loyalty to Konoha. Naruto's attack would go against Sasuke's current beliefs. Then there's Naruto's old friends like Choji and Kiba. They have grown up with Naruto in Konoha and would not let him harm the village. They would fight to protect their home and their friend from himself. Also, the ANBU black ops would be sent to stop Naruto as they are tasked with protecting Konoha from internal threats.
The traditionalist elders might oppose Naruto. They are used to the old ways of running Konoha and may see Naruto's takeover as a threat to their power and influence.
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.
Iruka sensei is almost certain to be in it. He has always been important in Naruto's life. Also, Sakura might be there. She could be one of the first to welcome Naruto or perhaps she might initially be a bit cold because of her past feelings for Sasuke. Other characters like Kakashi sensei could also make an appearance, guiding Naruto in his new life in Konoha.
Obviously Naruto would be one of the main characters as the title implies he's the one attacking. And the Kages, like Gaara, Tsunade, and the other village leaders would also be main characters since they are at the summit that Naruto is attacking.
Sasuke would likely be involved. He has his own issues with Konoha and might side with Naruto, either out of friendship or his own vendetta against the village. Also, the elders of Konoha like Danzo could be important characters as they might be the ones behind Naruto's banishment.
Obviously, Naruto himself would be a main character. His friends like Sasuke and Sakura are also likely to be important. Maybe their children could also play significant roles as they grow up in the post - return to Konoha era.
The village elders are very likely to be involved. They often have a say in the big decisions in Konoha. They might be the ones who decide that Naruto must return for the safety or the benefit of the village. Tsunade could also be a part of it. If she's still in charge, she might be in a difficult position of having to order Naruto back or deal with the consequences of his forced return.
Obviously Naruto himself is the central character. Sasuke would also likely be involved. Given their history and Sasuke's own complex relationship with Konoha, he might side with Naruto or at least be a key figure in the events. Kakashi too, as he has been Naruto's teacher and is an important figure in Konoha. He could be caught in the middle, trying to understand Naruto's motives and also trying to uphold Konoha's stability.
It could be Orochimaru. He has always had his eyes on Konoha and might find a way to manipulate Naruto into attacking it. Maybe he uses some new experimental jutsu on Naruto to make him do his bidding.