Well, the white horse is surely one of the main characters. There might also be a rider or a keeper of the horse. It could be a young boy or girl who has a special bond with the white horse.
In some short stories, the main character could be an old man who has spent his life taking care of the white horse. The horse might be the last remaining link to his past, and the story could revolve around his memories and the special relationship he has with the horse. There could also be a mysterious figure in the story who appears from time to time and has some sort of connection to the white horse.
Maybe there's a young boy or girl as a main character who is drawn to the beautiful white horse during the summer. And there could be an older person, perhaps a farmer or a stable keeper, who also has a role in the story related to the horse.
There could be the wonder horse as the central character. Then perhaps a young person, like a boy or a girl who befriends the horse. There might also be some antagonists, like people who don't understand the horse's value and try to harm it or take it away. There could also be other animals in the story that interact with the horse, either as friends or foes.
In 'the rain horse short story', the most prominent character is the man. He's the one through whose eyes we experience the whole story. The rain horse can also be considered a main character in a way, as it is the central element that drives the story forward. It's like an antagonist of sorts to the man, creating all the tension and mystery in the story. There might be some minor characters in the background, like people from the man's past or place he came from, but they are not really in the forefront.
The main theme could be about freedom. The white horse often symbolizes freedom in many stories. It might be about a journey of the horse or the character associated with it towards a state of freedom.
The main characters are the young boy, his mother, and his uncle. The boy is central to the story as he tries to earn money through his rocking horse rides.
Paul is the central character. He is a young boy who is very sensitive to his mother's unhappiness. He discovers that he can predict the winning horse in races by riding his rocking horse until he 'gets there'. His actions are driven by his love for his mother and his desire to gain her love through providing money.
Since I haven't read it, I can't say for sure. But it probably has the white knight as a main character, and perhaps there's a damsel in distress like a princess.
I'm not sure as the title doesn't give much away. But it could be a young girl who discovers the white flower and the story could revolve around her experiences related to it.
The woman in white herself is a main character. There may also be a protagonist who encounters her, like a young man or a curious person who gets drawn into the mystery of the woman.
Since we don't have a detailed version of 'the white elephant short story', it's hard to say exactly. However, it's common in such stories to have a protagonist who is directly affected by the white elephant. This could be a person who has received the white elephant as a gift or inheritance. There might also be secondary characters like neighbors or business partners who react to the protagonist's situation with the white elephant. They could either be sympathetic or critical, depending on the nature of the story.