They are speaking of only real events which makes it nonfiction.
The words “You don’t have to feel like a waste of space” meaning that you yourself are worth something so you are not a waste. “You are original, cannot be replaced” it means you are the only one out there. Nobody is exactly like you, so if you disappear no replica can be made. “If you only knew what the future holds” means that there is a lot of potential for you and it gets better in the future. “After a hurricane comes a rainbow” meaning that it always gets worse before it gets better. So in all it starts from telling you, you are something and someone and to keep in mind that it will be worse but in the future the rainbow will show the light of how it gets better.
I hope I explained well~~~
I think Mikai's starship reveals the setting. I think that would be space .
