Well, without more details, it's hard to say exactly who he is in the context of the ghost story. He could be the protagonist who experiences the ghostly events.
I'm not sure if there is a specific 'bang' related directly to a book by Barry Lyga in his stories. It could potentially be a very specific reference within one of his works that I'm not familiar with. You might want to check his official website or a detailed book review site for more information.
Perhaps there's a best friend character. This person could be a mortal who is initially unaware of Nancy's demigod status. As the story progresses, they might get dragged into Nancy's world and have to deal with the consequences. There could also be a villainous demigod who is trying to stop Nancy from achieving her goals or is causing trouble in the demigod world in general.
Ned Nickerson is a well - liked character. He is Nancy's boyfriend. He sometimes gets involved in the mysteries in a way that helps Nancy. And Carson Drew, Nancy's father, is also important. His profession as a lawyer sometimes ties into the cases Nancy is solving.
The art in these graphic novels is usually quite detailed. It helps to create the different settings, like the spooky old mansions or the small town streets where the mysteries take place. In 'Nancy Drew: The Secret of the Old Clock', the detailed illustrations of the old - fashioned interiors really add to the atmosphere of the mystery.
As far as I remember, in 'A Christmas Story' there was no character named Barry. The main characters were Ralphie, his family members like his mother, father, and his little brother. There were also the school bully and the Santa at the department store, but no Barry that I can think of.