Well, in addition to Tinkerbell and Peter Pan, including the fairies from Pixie Hollow would be amazing. They could come to Neverland on a special mission and interact with Tinkerbell in different ways. The Lost Boys are essential as they are part of Peter Pan's crew. And of course, Captain Hook. His presence always spices up the story with his evil plans and his rivalry with Peter Pan. You could also consider including the crocodile that chases Hook around. It could add an element of danger and suspense.
The main characters are, of course, Tinkerbell and Peter Pan. Tinkerbell is the feisty and magical fairy, always by Peter's side in Neverland. Peter Pan is the boy who never grows up, full of adventure and mischief.
Tinker Bell could be a great addition. She could be the mediator between Peter Pan and Captain Hook, or she could also be a source of jealousy for Hook if he has some unspoken feelings for her. Another character would be the Lost Boys. Their reactions to a possible truce or new relationship between Peter and Hook would add a lot of depth to the story. For example, if some of the Lost Boys are skeptical while others are more open - minded.
The relationship could be developed by having them share more secrets. For example, Tinkerbell could tell Peter Pan about a special place in Neverland only she knows. Also, they could face a big threat together, like a powerful villain, and in the process of fighting it, their bond grows stronger. Another way is for Peter Pan to show more appreciation for Tinkerbell's help, which makes her feel more important to him.
Peter Pan is likely to be deeply affected. Tinkerbell has always been by his side, so her death might make him feel a great sense of loss. He could become more withdrawn or reckless, as he has lost his faithful companion.
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.
The main characters would obviously be Peter Pan and Tinkerbell. Peter Pan is the boy who never grows up, always full of adventure and a bit of mischief. Tinkerbell is the feisty fairy who has a special connection to Peter Pan. In a lemon fanfic, their relationship might be explored in a new context, with the lemon aspect perhaps adding a bit of a zesty or different element to their interactions.
Nendo could be a great addition. His simple - minded nature can add a lot of humor. For example, he could misunderstand the relationship between Saiki and Kaidou and try to get in on their 'adventures' in a really clumsy way.
Well, one character that would be interesting to include is Commissioner Barbara Gordon. She has a long history with the Batman universe and can serve as a link between the old and new. In addition, Brother Eye could be a great addition. It's a powerful and complex entity that can create all sorts of plot twists. And don't forget about Inque. Her shape - shifting abilities can make for some really exciting and unpredictable story elements when combined with Batman and Barda's story.