It depends on the specific fanfiction. Each author might have their own unique portrayal of the character.
She could go to the mountains. The high peaks are often seen as a place of solitude and mystery in many stories. There, she might find a cave where she can hide and think about her life. It could also be a place where she discovers some long - forgotten magic that has been dormant for ages.
It could mean that she has read or been exposed to a sufficient amount of 'Encanto' fanfiction and doesn't want any more. Maybe she's found that a lot of it is repetitive or just not to her taste anymore.
They might be really surprised. Some characters could be flattered by the positive portrayals in the fanfiction. For example, Mirabel might be happy to see different interpretations of her story and how she's seen as a hero in some fics.
Some might be amused. It's a new and different take on their story, so they could find it fun.
She might have found that the quality of the 'Encanto' fanfiction she's been reading has declined. There could be a lot of poorly written or unoriginal stories out there, which made her decide she'd had enough.
There are also some Encanto - specific fanfiction communities on social media platforms. For example, on Tumblr, there are often users who share and recommend Encanto fanfictions. You can search for tags like #EncantoFanfiction and #Madrigals to find some great reads. Additionally, some Discord servers dedicated to Encanto might have channels where fans discuss and share their favorite fanfictions about the Madrigals.
One interesting storyline could be exploring the unshown daily lives of the Madrigals before the events of Encanto. For example, how Julieta manages to cook such magical food every day and what kind of experiments she might have done in the kitchen. Another could be a story about Bruno's time in the walls from the point of view of the other Madrigals, like how they might have unknowingly interacted with him without realizing it was him. There could also be a fanfiction focusing on the younger Madrigals and their playtime, and how their powers influenced their games.
It could be someone who is jealous of Mirabel's potential. Maybe a relative who feels that Mirabel's new - found importance in the family (even if she doesn't fully realize it yet) threatens their own status. For instance, a cousin who was once favored but now sees Mirabel as a threat.
I think Mirabel from Encanto and Aang from Avatar would be likely to interact. Mirabel is all about finding her place in the family and Aang is on a journey to save the world. They could share their experiences of feeling different and having big responsibilities.
Mirabel is often a main character. She has such a relatable journey in the original story, and in fanfiction, she can be further explored. For instance, her relationship with her family members can be deepened or new adventures can be created for her.