For the original story of 'Peter Pan', the main characters are Peter Pan himself, Wendy, John, Michael, Tinker Bell, Captain Hook, and the Lost Boys. Peter Pan is a boy who never grows up and takes Wendy and her brothers to Neverland, where they have various adventures with pirates like Captain Hook.
In the original 'Alice's Adventures in Wonderland', the main characters are Alice, the White Rabbit, the Cheshire Cat, the Mad Hatter, and the Queen of Hearts.
In the original 'The Wizard of Oz', the main characters are Dorothy, who is the protagonist, Toto (her dog), the Scarecrow, the Tin Man, and the Cowardly Lion. Dorothy is swept away to the magical land of Oz and embarks on a journey to find the Wizard of Oz to get back home.
If it's a different '300 original story', perhaps the main characters are the leaders of the 300. For example, if it's a group on a quest, the ones who are in charge of leading the 300, making decisions, and guiding them through the various trials and tribulations would be the main characters.
In the original batman story, there are several main characters. Bruce Wayne, who is Batman, is of course central. He is the one on a mission to save Gotham. Alfred, his butler, is a very important character as he provides support, both emotional and practical, to Bruce. Commissioner Gordon is also a main character. He is an ally of Batman in the fight against crime in Gotham. He helps Batman in various ways, like sharing information about crimes in the city.
The main character is Charles Lee Ray, the serial killer whose soul gets transferred into the doll, and of course, Chucky the doll itself.
The main characters are a priest and a novitiate. They are the ones sent to the abbey to deal with the situation regarding the possessed nun.
The main characters in the 'Pitcairn Original Story' are likely the Bounty mutineers. They were the ones who initially settled on Pitcairn Island.
Since I'm not sure which specific 'cabaret original story' you mean, it could be the performers. For example, singers, dancers, and comedians who were the heart of the cabaret shows.
The main character is Conan, of course. He is the central figure around which the story revolves.
The main characters are Devdas, Paro, and Chandramukhi. Devdas is the tragic hero in love with Paro. Paro is the woman he loves but is separated from. Chandramukhi is a courtesan who falls in love with Devdas.
The main characters in the original Nemo story are Nemo, Marlin and Dory. Nemo is the young fish who gets captured. Marlin is Nemo's father who goes on a journey to find him. Dory is the forgetful but helpful fish that accompanies Marlin.
The main characters are Cloud Strife, a former SOLDIER. There's also Aerith Gainsborough, a flower girl with a special connection to the planet.