Let us analyze the storypoints of "Finn the Human" and "Jake the Dog."
- The Lich destroyed the world and created Ooo in the process. Also, the Lich may have been human at some point, because Jake turned into the Lich after the missile exploded.
- Upon further thought, the Lich could have been anything, probably a human or some sort of goat.
- Apparently all the people in Ooo would have been human if not for the Mushroom War.
- Upon further thought, it was probably just the humanoid creatures who would have been human (Which is why Jake is a dog while Choose Goose is Choose Bruce).
- Apparently the Ice King Crown causes Obsessive Compulsive Disorder over what the person was concerned about at the moment he put on the crown (Ice King became obsessed over princesses, Finn became obsessed with freezing everything).
- Whatever happened to the Lich and Billy after the final wish was granted? And what went down in the Lich's universe after he wished for the extinction of all life?
If you have any other points you like to point out, please do so in the comments.