What do you think the three older boys in the ghost story are?

It is possible that the three older boys in the ghost story are ghosts. The old man says that they died long before the events in the story, and it is clear that he could not have been a young boy at the same time as the narrator. However, the old man still seems to be alive, making it unlikely that the narrator saw his ghost many years ago. Instead, the three boys probably represent the spirit of youth. They are some kind of incarnation of the boys that played there as children, without actually being ghosts. They disappear inside the playhouse because something horrible happened here that took away their innocence.