A teacher at her school could also be an important character. The teacher might notice the girl's strange behavior due to her secret and try to help her. This could lead to a series of events where the girl has to decide whether to trust the teacher and reveal her secret or keep it hidden.
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.
Perhaps it's about a special talent she has been hiding. For example, she can paint amazingly well but has been keeping it a secret because she's afraid of being judged.
Lily Owens is a very important character. She's the protagonist, a young white girl on a journey to find out more about her mother. August Boatwright is also key. She's a black beekeeper who takes Lily in and becomes a mother - like figure to her. And then there's Rosaleen, Lily's nanny who is also an important part of the story.
Mary is an important character. She is the protagonist who discovers the secret garden. Dickon is also important. He has a great knowledge of nature and helps Mary in the garden. Colin is another key character. He is a sickly boy who is transformed by the magic of the garden and his friendship with Mary and Dickon.
Lucy herself would surely be one of the main characters. And maybe she has a best friend in the story, like a character named Lily who helps her through all the challenges.
There's Mary Lennox, a complex character who evolves throughout the story. Her discovery of the garden sets in motion many of the events. Dickon, with his love for nature and his gentle spirit, is an important presence. He helps bring the garden back to life. Colin Craven, a boy with a lot of emotional and physical problems, is also vital. His relationship with Mary and the garden is what helps him overcome his issues. Mrs. Medlock, the housekeeper, while not as positive as the others, is also an important character as she sets the tone in the manor at the beginning of the story.
The magic gourd itself can be considered an important 'character' in a way. It has its own power and rules for granting wishes. It is the central element that drives the story forward.
There is usually a protagonist who drives the story forward. Maybe a detective or an ordinary person who gets involved in a complex situation. And there are likely to be supporting characters like the love interest of the protagonist, friends or colleagues who help or hinder the protagonist in their journey.
In many 'the orphan girl story' variants, the orphan girl is central. Then there might be a villainous figure, perhaps someone who tries to take advantage of her situation. And there could be a mentor - someone who gives her advice and helps her navigate the difficult world she's in. For example, an old lady who has seen a lot in life and teaches the girl valuable lessons.