The basic similarities among all these highly distinctive characters related to their structural positions within their respective societies. All are members of groups that have experienced discrimination or been disadvantaged because of biases.
For Laila and Mariam, this disadvantage relates to gender imbalances in Afghan society under the Taliban—particularly to their relationships with Rasheed, their violent husband. Mariam's resistance, through killing Rasheed, brings down the weight of the legal system that condemns her. For Tariq, although he is a man, discrimination forced him and his family to flee their country, and he suffered as a refugee and prisoner.
Hassan experiences severe discrimination because of the historical animosities between different ethnic and religious groups in Afghanistan. He is a Hazara and follows the Shia variant of Islam. He is also the target of a violent sexual assault by other boys because one sadistic boy uses those social biases to justify his vicious behavior.
Dane's situation is somewhat different because he does not know the truth about his father. In fact, he is illegitimate. His mother hides this fact to protect him from discrimination as well as to shield his biological father and protect her reputation. Dane has some commonalities with Tariq in that both are generous and make sacrifices, even for perfect strangers.