I believe the John Osban was born about 1805 (he was 55 in the 1860 Clarendon Co., SC census) I have a deed in which William Garner states that John Osban is his step-son (dated 20 Sept. 1839 Deed Bk N, pg 330-331).Mary Byrd was born 16 Jan 1814 the daughter of Miller Byrd and Nancy Parrott.I am not sure when they were married. I do have some land deed records for John Osban.
John may be the son of Demsey Osborne who was baptized at Welsh Neck Church on 21 Jun 1829.Demsey was deceased by 3 Jan 1861 and there is a deed listing his heirs in Deed Bk T, pg 546 as Charity, Hannah, John and Catherine.
I was told by a cousin that her family thought that the OSBAN family came from Switzerland. I have no documentation that would indicate that to be true.