There might be a young fairy who is on a quest to discover the secrets, and she could be one of the main characters. Also, there could be an antagonist, perhaps another fairy who wants to keep the secrets hidden at all costs. There could also be some human characters if the story involves the interaction between the fairy world and the human world.
The main character is Barbie, of course. Then there are likely to be fairy characters. Maybe a friendly fairy who helps Barbie understand the fairy world, and perhaps an antagonist fairy who creates problems for Barbie.
In the secret fairy garden story, the main characters are likely to be the fairies. They would be the ones who live in the garden and create the magical atmosphere. There might also be a human character, perhaps a little girl who is lost in the forest and stumbles upon this secret place. And there could be some small magical creatures like pixies or sprites that help the fairies in the garden. These characters would interact with each other, with the fairies teaching the human about their world and the human bringing a different perspective to the fairy garden.
Given the lack of context regarding the 'bastos secret secret story', we can only speculate about the main characters. If Bastos is a person, perhaps they are the central figure, and there could be friends, family members, or foes around them that are part of the story. Maybe there are also some mysterious figures that help or hinder Bastos in the discovery or protection of the secrets in the story.
Since I don't know the details of this story, it's hard to say. It could be pilots, aircrew members if it has something to do with a plane - related event on the tarmac. Or it could be spies if it's a story about espionage and the tarmac is the location for a secret exchange.
There could be a curious child as one of the main characters. This child is always exploring and it's their inquisitiveness that leads them to the secret door.
As we have no prior knowledge of this story, it's hard to tell. It might have a protagonist who is on a journey to find the secret book. There could also be an antagonist who wants to use the book for evil purposes. And perhaps there are some side characters like friends or family members of the protagonist who play important roles in the story.
I'm not sure exactly who the main characters are without reading the story, but it could be a young child who discovers the secret lion.
Since I'm not familiar with 'the secret miracle story', it's hard to say. However, it could have a character who is in search of the secret miracle and along the way meets other characters who either help or hinder this search. There might be a wise old figure who knows something about the miracle or a young and curious person who stumbles upon it.
Since I don't know the specific 'Secret Room Story', it's hard to say. But usually, there could be a curious explorer who discovers the room, and maybe a villain who wants to keep the secrets in the room hidden.
Since I don't know the specific 'Secret Service Story', I can't say for sure who the main characters are. They could be secret service agents.