It has been a while since you posted your question and you may have the answer by now. If not, there is a grave for Caleb Crofts on findagrave .com in the Crofts Family Cemetery in or near Etowah [McMinn County] TN. No dates are given and he is the only 'occupant' listed. There is considerable info, including pictures, in a private family tree on Ancestry.com. His birth year is given as 1830. In 1890, C. J. Crofts married E.J. Griffith in McMinn County and died in 1891, as you said. He was in Lillards outfit. Feel free to contact me at egr199@gmail.com if I can help.