Found you while researching the O'cains. Sounds like my guys. Here's what I have.
William W. O'Cain was born August 21, 1828 in Sumter County, SC. He died October 25, 1911 in Lake City (Columbia County), Florida.
Callie Hutchinson was born in South Carolina and married William on November 6, 1868 in Columbia County. I don't have birth or death dates for her yet.
The info on William comes from his Civil War Pension Application, made in Columbia County in 1910. The info on their marriage comes from county records. His death date is from Callie's widow's pension application made in 1911 after he died.
His application stated that his family moved to Florida in 1857. I found a note in a newspaper obit for a Louisa M. O'cain, 1837-1870 in Sumter County, SC whose family moved to Columbia County, FL in 1857. I'm assuming that she was his sister.
William and Callie had one child I know of for sure, Lula Addie O'cain. She was my Dad's grandmother and she was born in 1869 and died in 1944, all in Columbia County.