While there is surname overlap, to be sure, I don't see any geographic or personal name connections. My Horns are pretty well documented in Cheraw, SC and then Thomas County, GA for most of the 19th and early 20th century and none of the names you're mentioning fit my current files.
There is another published source for Sneads --no help to me at all, btw--it seems to focus mostly on Virginia:
The Sneads of Fluvanna / Oranie Virginia Snead Hatcher;Virginia Bagby DeMott Cox 1959 [2d ed.]
It's the Snead/Horn connection to other Snead lines that continues to intrigue me -- as I said, the name conservation is striking and there must be some connection. But I don't think we've got one between my folk and yours.