The above screen shot is a graph of William Wells Brown’s Clotel (A text published before the Civil War). Interestingly it follows the trend of Uncle Tom’s Cabin (another pre Civil War text) in that as you move further into the narrative, the story becomes more concerned with death. The other two terms mostly remain the same.
The above screen shot is a graph of Iola Leroy (a text published after the Civil War), and interestingly, Iola Leroy seems to follow the same trend as Adventures of Huckleberry Finn.
These two graphs help validate my early thoughts going into this project. There does seem to be an empirical difference in the way writers are engaging with the theme of death before and after the Civil War.