Murchison represents "assimilation" and "assimilationist values". We see this in his tone of voice - his haughtiness, his pride, and his sense of entitlement. He is presented with only the barest amount of sympathy.
Willy Harris is the "street" figure. He exemplifies the "low morals" of the crook and the schemer. In some ways he is just like Walter Younger, but does not have the same pride that Walter ulitimately proves to have.
Mr. Linder represents a wider, background or outsider perspective than any other character and is direclty aligned with an apologetic racism that is unsoftened by its apology.