The records I have are from my grandmother.

According to her, Johnathon and Samuel were brothers. Johnathon and Martha Higginbottam's childern were Bill, Mary (Molly), Florence, Nancy, & George. There may have been others including the ones you mentioned. I have no information about where any of them went.

Bartow County was orginally named Cass County until December of 1861.

Other resouces that may be useful are:
http://www.bartowhistorycenter.org/
http://www.gabartow.org/

Good luck and keep us posted.
Brian