The previous thoughts were extremely strong. I am in complete agreement that books could be written on the topics featured. I would say that the fragmented nature of the narrative as stressed in postmodernism is present in a couple of ways. The first is that there is little coherent structure in narration present. We really do not know the main character, and the primary character we do know, Tyler, is actually the narrator. In understanding the relationship between Tyler and Marla, we actually understand that the relationship was between Marla and the Narrator. At the same time, the overall postmodernist theme is present when we understand that the life "laid out" for the narrator is rejected and in its place is a new one without much in the way of structure or order. The temporary imposition of this new life is also one that contains fragmented approaches to consciousness, for at the end, the narrator seeks to bring a change to this way of existence as well, proving the post modern theme that there is no totality in consciousness.
This is a huge question. So, let me just answer one of them - postmodernism. A good way to look at post-modernism is the lack of a totalizing narrative. Post-modernism does not like neat organizations and categories, because post-modernism realizes that the world is a complex place. Moreover, categories and totalizing stories are usually just man-made attempts to control the minds of people by those who have power. If we look at post-modernism from this perspective, the movie, Fight Club, is very post-modern. It is completely anti-establishment. There is no unity. There is no totalizing narrative. In fact, the core of the movie is just the opposite! It is schizophrenic.