I'm not sure who Hadley Duvall specifically is as the name isn't widely known without more context. It could be an ordinary person with a personal story, or perhaps a name within a specific community, family, or a relatively unknown field.
Character growth is a big characteristic. Since he is a somewhat controversial character, many fanfics aim to show his development. They might show him learning from his experiences, like in a fanfic where he has to face the consequences of his actions and becomes a more empathetic person. Also, his relationships with other characters, whether it's a rivalry or an unexpected friendship, are central in Cato Hadley fanfic. In some stories, his relationship with a fellow tribute can completely change the course of the story.
If this is related to a story that has a group of characters, Cato Hadley might be the male lead in the love story. Maybe he is a brave and charming character, or perhaps he has some flaws that make the love story more complex. But again, this is all speculation without further information.
I'm not sure exactly who Michelle Brown is without reading the story in detail. But she is likely the victim of identity theft in this particular account.
I'm pretty sure there isn't a Michelle in the Spiderman comics. The comic characters are pretty well-defined, and Michelle isn't one of them. But you never know, there could be a new character introduced in future issues.
One of the highly regarded James Hadley Chase novels is 'No Orchids for Miss Blandish'. It's a gripping crime story with complex characters and a dark plot that keeps readers on the edge of their seats.
In the Capitol, before being sent to the arena, Cato and I were in the same holding area. I was scared out of my wits, and he could see it. Instead of taunting me like some of the other tributes might have done, he sat beside me and said, 'Don't be afraid. I'll look out for you if I can.' His words were like a warm blanket in the cold reality we were facing. Once in the arena, we were on opposite sides at first. But fate had other plans. One day, I was injured while trying to get some water. Cato found me. He could have ended my life right there, but instead, he picked me up and carried me to a safer place. He tended to my wound, and as he did, our eyes locked. There was an unspoken understanding between us, and that was the start of our love story.