Do you have names of other family members who lived during William's time or maybe an estimated year of William's DOB, DOD, or marriage date(s)?

I am not sure if the following individuals are Black or White:
Thomas H. Middleton married Elizabeth McCraine 08/08/1839
George Middleton married ? 12/20/1882
William Middleton married ? 12/20/1882 at Bethel Church
Sam Middleton married ? 12/20/1882 at Bethel Church

Have you assumed that William took the surname of his owner? In the book Masters of the Big House by William K. Scarborough, there are listed several (11) slave owners having the Middleton surname. All had plantations in SC and NC; unfortunately no MS MIddleton plantation owners are given.