One reason could be to escape her current situation. Maybe she was in some kind of trouble or was tired of her life as it was. Another reason might be to deceive those who knew her. Cathy seems to be a rather manipulative character, so faking her death could be a way to gain some sort of advantage or freedom.
In Steinbeck's 'East of Eden', Cathy fakes her death. Cathy is a complex and often immoral character in the novel, and this act of faking her death is part of her devious nature and her attempts to manipulate those around her.
As I don't know the Cathy Mahone story, I can't say who she is specifically. She could be an ordinary person with an interesting life story, or she might be someone well - known in a particular field.
The Black and White Ghosts died because they encountered a rainstorm when they were out. At that time, they had discussed that Fan Wujiu would wait by the bridge while Xie Bian went back to get the umbrella. However, due to the heavy rain, Fan Wujiu was quickly submerged. Xie Bian, who was waiting by the bridge, discovered Fan Wujiu's death and then hanged himself.
The cause of death of the Black and White Ghosts was that Fan Wujiu was drowned by the heavy rain while waiting for Xie Bian to come back to get an umbrella. When Xie Bian came back and found Fan Wujiu dead, he felt guilty and hanged himself. This story expressed the feelings of Fan Wujiu dying because he kept his word, and Xie Bian dying because of guilt. It left a deep impression on people.
I don't know who the author of the 'white death novel' is. There are so many novels out there and without more information, it's impossible to determine the author.