I don't know where to place this - maybe just on www.wikepedia.org - pass. I haven't been following wikepedia developments, and I don't know where it stands on the cultural landscape.
I've read neither story. That said, your comparison is thorough and persuasive, though I'm unable to comment knowingly on the "manifestation of modern America’s penchant for self-analysis, gratuitous confession and exhibitionism".
But is this merely King acknowledging how similar the two stories are, or is “Dolan’s Cadillac” in fact a modern version of “The Cask of Amontillado”? - or what's the diffence? You end by plumping for the "modern version" option, but the question/conclusion sound too much like mere essay-shaping ploys.