If you are still out there.....I called Fort Pillow yesterday morning after our conversation and was given the email addresses for two men at Fort Pillow to talk to. I wrote them and their reply was:
"the only soldiers that were buried here after the battled ended on April 12th were colored soldiers with the Union Army. Most of the info we have states that the Confederate Soldiers were buried in Memphis, or carried back home. The info I have on your grandfather is 5th Mississippi company C, Killed. I would check the National Cemetery in Memphis to see if your grandfather is there".
I have a real problem thinking that they were buried in Memphis as the bulk of the troops were headed east toward Jackson, Tennessee not south towards Memphis. So I am still at a deadlock for where my g-g-grandfather was buried.