it may be a little late, but i thought i might help you on the matter of religion being of importance to the kite runner.
as a matter of fact, the importance of not only religion but culture and 'watan' is of the most importance in this novel.
religion plays a part in the way that amir and hassan as well as their fathers lived their lives, and in most cases their decisions and actions are made from the roots of their faith.
culture can also be used in regards to religion as the author uses this in many aspects of his novel. for example, when hassan is getting raped amir refers to the sacrificial act of the lamb. this is a cultural take on the event. there are also many other examples of this.
last but not least, watan, which most do not understand is the simple act of belonging to a place. in refereance to the kite runner, when baba mentions that his watan is afghanistan he is simply stating that he would die for his country. it is simple devotion. there are also many examples of watan in the novel.
hope i could help and give you a few more resources.