The characters in Dragonwings demonstrate their sense of principles by helping others. Moon Shadow, for example, is an extremely disciplined kid who consistently looks out for his dad's best interest over his own. Throughout the novel we see characters acting in generous ways. At the end of the day, Dragonwings suggests that people who look out for other people are way more awesome than those who just think of themselves.
Black Dog is the strongest character because he works outside of the law, subverting rules of the Man.
Mother is the strongest character in Dragonwings because she patiently takes care of her own life while offering as much support as possible to the ones she loves.