For another story I'm doing (and I might use it here too)- (This is derived from various silver age comics, and the Kents)
Ely Kent was a revolutionary era blacksmith, his son Joshua was a barge captain on the Erie Canal. His son Silas was a Boston publisher, (wife named Abigail Colter). Silas and his two older sons (Nathaniel and Jebediah) moved to Kansas prior to the Civil War (Silas was firmly pro-abolitionist and was murdered for his opinions). Nathaniel and Jebediah ended up on opposite sides during the war and Jebediah ran with Quantril's raiders. Nathaniel became a sheriff, married Mary Glenowen (Who was half Welsh and half Delaware) and ended up in Smallville. Jebediah ended up dead after a foiled attempt to rob the Smallville bank in 1874.
We aren't given the names of Nathaniel's and Mary's children so a generation is missing, but they had at least one boy and one girl.
Jonathan's father's name is given as both Hiram and Matthew (depending on source). I haven't found a name for Jonathan's mother.
In the silver age comics, Jonathan had a brother named George who was a merchant seaman and died when Clark was young. He also had a sister named Minerva who ended up marrying Zachary Barnes late in her life.
In LnC, Clark (or either Martha or Jonathan) has an Aunt Opal in Metropolis.
Smallville has Martha's father's name as William Clark, no name given for his wife.
