Iruka Sensei could also be a candidate. He was one of Naruto's first supporters and has a deep connection with him. He would probably risk a lot to save Naruto.
Kakashi Sensei. He has always been a mentor to Naruto and the others. His skills and his sense of responsibility towards his students would likely drive him to rescue Naruto if he found out Naruto was left for dead.
Obviously, Naruto would be a main character. His determination and powerful jutsu would be crucial in the rescue mission. Gaara, the Kazekage himself, would also be a central figure even though he is the one being rescued as his past and his role in the shinobi world are important aspects.
Kakashi could also play a role. He has always been a mentor to Naruto and his sense of duty and loyalty to his student might drive him to search for Naruto when he hears that he's been left for dead. He has the skills and knowledge to find and save Naruto in a difficult situation.
Most likely Naruto himself would be one of the main characters. He's the titular character of Naruto. And probably some of his close friends like Sasuke and Sakura. From High School of the Dead, it could be Takashi Komuro.
The Akatsuki members could also be involved. If Naruto returns from the dead, they might see him as a threat to their plans or as an opportunity to use his new - found power for their own purposes. For example, Pain might be curious about how Naruto managed to return and what new powers he has.
It could be a rogue ninja from another village who has a vendetta against Naruto. This ninja might have set a very elaborate trap that made it seem like Naruto was killed and left his body in a place where his friends would find him and think he was dead.
Most likely Naruto himself would be one of the main characters. Since it's a Naruto - based fanfic, he would bring his ninja skills and determination to the high - school - zombie scenario.
Kakashi could also be involved. Maybe he's put in a difficult position where he can't save Naruto for some reason, like being under a powerful genjutsu or being blackmailed. This would create an interesting conflict as he's Naruto's teacher and mentor.
Kakashi could be another important character. As a mentor figure, he might be guiding the younger generation through the difficult times after Naruto's death, using his experience and wisdom to keep the village stable.
Sasuke is a likely candidate in some fanfictions. Given their complex relationship throughout the original series, it's easy to imagine a scenario where Sasuke's thirst for power or some misinformation leads him to betray Naruto. Another could be Sakura. If she becomes jealous of Naruto's growing power or if she's manipulated by outside forces, she might turn against him.
The Cullens are the most likely. Edward, with his mind - reading ability, can try to sense where Renesmee is. Bella, with her strong will and vampire strength, would be at the forefront of the rescue mission. And Carlisle, with his wisdom and leadership, would plan the whole operation.