Think about a particular motif, pattern or theme that you can focus on in your essay. Discussions in which we disagreed about the “right” interpretation are especially good as the basis for an essay. There’s no need to try to reach a neat conclusion at this stage. Instead, try to identify details of The Adventures of Huckleberry Finn. that are interesting and meaningful.
Your own post about Huck as an unreliable narrator would be a great focus for your essay: why not point out several passages in Adventures of Huckleberry Finn that show Mark Twain’s perspective or values as different from Huck’s?