Who might be the main characters in Lucy's secret fanfiction?

Well, obviously she'll interact with her past self. It would be really interesting to see how she reacts to seeing a younger and more naive version of herself. She could also meet characters who are no longer alive in the present. For example, if there were any great wizards from the past who played important roles in the history of magic. Additionally, she might cross paths with some of the villains from the past who were causing trouble long before the current villains in the story. This could change her perspective on the whole conflict in the present.

Sakura is the main focus. Alongside her, there could be a new character who she meets by chance and who somehow gets involved in her secret. This new character could be from a different place or group and has their own motives regarding Sakura's secret.

Her best friend could be important. The friend might offer emotional support, babysit sometimes, or give Lucy some parenting tips that she learned from her own family.

Erza would be one of the main characters affected. In the original story, when Lucy joins, Erza has a certain perception of her. But if Lucy joins earlier, Erza might see her as a more inexperienced mage and take her under her wing even more. Gray might also have different interactions with Lucy. He could be more of a mentor figure to her in the beginning, teaching her about controlling her magic in cold environments, which is something he's good at.

Maybe there's a group of dragon hunters. They view Acnologia as the ultimate prize and would do anything to capture him. When they see Lucy interacting with Acnologia, they consider her a traitor to humanity and try to take them both down. They could be the main antagonists as they constantly pose a threat to Lucy and Acnologia's new - found relationship.

Laxus could be seen as the main antagonist in this scenario since he is the one who kidnaps Lucy. However, it could turn out that there is a greater force behind his actions, in which case that unknown entity would be the true antagonist.

It could be her long - lost sister. They might be reconnecting through texts after years of being apart, and the mom wants to keep it a secret until she figures out how to tell the rest of the family about this newfound relationship.

Well, the sister herself is obviously a main character. And perhaps her best friend who might be the only one she has confided in about her secret.

Gray could be a supporting character. He might be passing by and end up getting dragged into helping Lucy, reluctantly at first. Levy could be another. Since she loves books and knowledge, she could offer some help in deciphering the more complex parts of the guild paperwork. And of course, Wendy could be there to offer her gentle support and maybe some healing magic if Lucy gets too stressed.

It could be her best friend. Her best friend might be the one who accidentally discovers Bella's secret in the fanfiction. And then they have to deal with the situation together, whether it's keeping the secret or helping Bella face whatever the secret entails.