Who is John and Tom McPherson from Out on a Limb and what is their importance?

John and Tom MacPherson are two of Kevin's spirit guides. John is an ancient spirit who speaks in Biblical English. He often uses language that is so difficult to understand that he stops speaking and allows another spirit to speak. Tom MacPherson was once an Irish pickpocket, who chose to continue with that persona from the spirit world because he so enjoys that particular incarnation. John and Tom tell Shirley some about her past lives and speak with her about religion and spirituality in a way that helps her to understand more about the concepts she is struggling to learn.