This may not be much help - but a researcher on ancestry.com has the Henry T. Calhoun from Tallahatchie County shown as Henry Townes Calhoun. They link the 1860 census you referred to, and also show him in 1870 in Coffeeville - Yalobusha County. They list his dates as 30 Nov 1833, Abbeville, SC to 27 Aug 1871, Charleston, MS. They do not show a burial location.