In my opinion, Rock Lee would be an interesting character to include. His admiration for Sakura could create some jealousy in Gaara. Also, Hinata could be added. She could be a confidante for Sakura, and they could talk about their relationships. Shikamaru might be a good character too. His intelligence could be used to help Gaara and Sakura solve problems in their relationship or in the plot. For example, if there are some political issues between Konoha and the Sand Village that affect their relationship, Shikamaru could come up with solutions.
Temari could be a great addition. As Gaara's sister, she could play a role in either supporting or being skeptical of their relationship. Naruto could also be included. His friendship with both Gaara and Sakura could add some interesting dynamics. He might be the one to encourage them or accidentally create some comical misunderstandings. Kankuro could be another character. He could provide some insights into Gaara's past and how his relationship with Sakura might change things in the Sand Village.
Well, one character that would be great to include is Ino. She could be the one who gives Sakura relationship advice or tries to interfere in a funny way. Sai could also be included. His lack of understanding of emotions could lead to some humorous situations when he tries to figure out what's going on between Gaara and Sakura. Another character could be Tsunade. As Sakura's mentor, she could have an opinion on Sakura's relationship with Gaara and might even set some conditions or give warnings, which would add more drama to the fanfiction.
Well, I think Shikamaru would be an interesting character to include. He's smart and could help Naruto with any strategic decisions related to their future as a family. Hinata could also be part of it. She's always been kind - hearted, and she could be a source of emotional support for Sakura. And of course, Jiraiya. Even though he's passed away, his teachings and influence on Naruto could be shown through flashbacks, like Naruto remembering the lessons about family that Jiraiya taught him.
Petunia could be a great addition. Her relationship with both Harry and Vernon adds a lot of complexity. She could be the mediator or the one causing more trouble between them, depending on the plot.
Ino. Since she is Sakura's friend, she can bring in some girl - talk moments. She could also be a bit jealous of Sakura's relationship with Sasuke at first, but then come to accept it and even help them out in some situations in the fanfic.
Naruto could be a great addition. His friendship with Sakura and his complex relationship with Kabuto in the original series could add an interesting dynamic. For example, Naruto might suspect something is going on between Sakura and Kabuto and try to interfere or understand what's happening.
The main characters are clearly Gaara and Sakura. Gaara is often depicted as a complex character with a troubled past, and in a high school setting, he would bring that depth to his interactions. Sakura, on the other hand, is usually strong - willed and intelligent, which would make for an interesting dynamic with Gaara in the high school story.
Metro Man could be a great addition. His presence could add some tension or an interesting dynamic, especially considering his past relationship with Megamind. Minion, Megamind's loyal sidekick, is also a must - include. He could provide comic relief and his unique perspective on Megamind and Roxanne's relationship. And maybe the Warden, who could be involved in some sort of prison - related subplot or just add to the overall chaos in the story.
Sasuke could be a great addition. He might initially be skeptical of Naruko's newfound bond with the Kyuubi, but then come to see the potential in it. Kakashi could also be included as he has a lot of knowledge and experience. He could offer guidance to Naruko on how to handle the Kyuubi's power. Another good character would be Jiraiya. He could have some interesting insights into the relationship between Naruko and the Kyuubi, having known about the Kyuubi for a long time.
The King and Queen of the kingdom. Their presence can bring in the political and parental aspects. They might have different views on how Rapunzel and Cassandra should handle certain situations, which could create more conflict and plot twists.
Gaara's unique sand abilities and his connection to the tailed beast within him can add a lot of depth to a fanfiction. Sakura could be curious about this part of him and through her curiosity, they bond. Sakura's medical ninjutsu skills are also something to consider. Maybe Gaara gets injured and she has to use her skills to heal him, which leads to a deeper emotional connection between them as they talk during the healing process.
The Akatsuki members would be the main ones. It could include Itachi, who is known for his complex character and powerful abilities. His relationship with Sakura could be an interesting aspect, whether it's one of mutual respect or a more adversarial one.