I have a listing of Carter Co graves, over 20,000 names. This list contains no name as John Leander and Elizabeth Erwin. My list contains two different Erwin cemeteries. One of these Erwin cemteries have two stones that I cannot read, so they may be what you are looking for. I have digital pictures of the grave stones and will send them to you for your inspection if you want. Additionally, I do not know the location of either one of these cemteries.