I have the book by Hobart Sebastian of Wilkes Co., "The Chronicle of a Southern Family", published in 1972. It lists the marriage of Benjamin II and Elizabeth, m. 1833, and it lists Madison and Sallie Beamon Sebastian's children. It is hard for me to follow his organization of this material. Perhaps you can make more sense of it. If you will send me your snail-mail address I will send you copies of these pages.
I am descended from Martin Chandler, b. 1799, and indentured to Elijah Sebastian in 1801. Martin took the Sebastian name, and is named in Elijah's will. This family moved to St. Francois Co., MO, in the early 1800s. Every hear of them? I have searched for many years for the names of Martin's parents.