I will appreciate if anyone helps me answer this: How does the characters in the novel reflect the concept of "self" in relation to others.

I think the protagonist Cole really doesn't have a sense of "self". Cole struggles to find himself but can't get past his anger, denial and self-loathing. Cole's mentors Edwin and Garvey have a sense of self through their own culture and perhaps trials similar to Cole. They know Cole has a strong sense of person buried down deep; he just needs to face hid demons and find it.