I think I may well have driven up your driveway when I visited the cemetery back in July 2011.
To the best of my knowledge, there aren't other family members buried in the cemetery besides the ones whose initials are given on the stones. Since none of Benjamin's children seem to have married, they didn't have children themselves.
Samuel had lived in Louisiana up to the year before his death. He had had two wives, both of them dead by the time he died (and he had divorced the first of the two, my ancestors Eliza Jane Smith--if, in fact, he ever actually married Eliza Jane).
When Eliza Jane died in Natchitoches Psh., LA, in 1843, she left all of her property to her son by Samuel, Ezekiel Samuel Green. When Ezekiel came of age to claim the property--which included a number of slaves--Samuel denied he had ever married Eliza and that he was Ezekiel's father, and, sadly, the son ended up suing his father for ownership of his property.
This case was first held by Pointe Coupee court, since Samuel was living in Pointe Coupee Psh. by this point, and the court found strong evidence that even if Eliza and Samuel had not married, they had both always acknowledged Ezekiel S. as their son and had jointly supported him after they separated. Samuel then appealed to the LA Supreme Court, which upheld the lower court's decision, saying it was not very admirable for a man to try to bastardize a son to obtain his property.
It was right after this verdict was handed down that Samuel seems to have gone to TX. I suppose in many ways his life and family connections in LA were broken, and he went to live with his brother at the end of his life.
He had by this point obtained a tract of land in TX in Llano Co., which ended up going to his son Ezekiel at Samuel's death. Ezekiel is my great-great grandfather, by the way.
Samuel and Benjamin did have a sister who also went to TX--Jane Caroline Green (1808-1897), who married Thomas Keesee. This couple and most of their family are buried at Ovila in the cemetery of Shiloh Presbyterian church. Benjamin initially went to Saline Co., AR, with Thomas and Jane Caroline, before he moved to Washington, and then Grimes/Waller Co., TX, and they to Ovila.