Science fiction is broadly defined as a genre of fiction that explores ideas that are currently out of reach of man, based usually in futuristic technology or an event that is feasibly possible but currently out of the realm of human experience or understanding.
The first option does not stretch the limits of what people have experienced. It is possible and perhaps even mundane in the realm of human experience, and thus is not science fiction.
The second option can be considered science fiction, as the narrator experiences something outside the realm of current human experience but within the laws of nature, and potentially something that humanity may experience in the future.
The third option would be a nonfiction historical account of a real event, quite far from the concept of science fiction.
The fourth option would be very easily considered science fiction. It involves an invention beyond the capability of modern science and imagines the consequences and experiences that would come with such a device.
Vonnegut may have wanted to appeal to readers' interests in prophecies about the future. ... Vonnegut almost certainly wanted to mock the growing emphasis in his day not simply on equality of opportunities (which most people endorse) but equality of outcomes (which many people think is impossible to dictate).
Base on my own research and further understanding, I would say that the answer would be that they are important because the creature realizes upon reading paradise lost that he resembles Adam and Satan and that there are many parallels in their relationship to their creator and in his relationship to his creator.
