Bob, I may be wrong, but I don't think this is your John. As far as I can tell, his wife and three of his sons (James, Isaac and Eli) had settled in Lincoln County, Tennessee by 1820, but I think he may possibly have died before then, because James was the head of household in the 1820 census. By the way, it was Eli, not John, who had a son named Owen. I'm pretty sure John, who seems to have been Eli's father, was the son of Owen Forrester of Spartanburg County, and Owen may have had a son named Thomas, although one researcher thinks Thomas was a nephew rather than a son. I seem to recall that this Thomas stayed in Georgia, but this is not my family line and I can't seem to lay my hands on the records right now.
Even if he lived past 1820, I really don't think this John would have come to Missouri after the Civil War, for the simple reason that he would have been about a hundred years old. He was already married with five children when he was enumerated in the 1790 census of Spartanburg County, which means he was presumably born in the 1750's or 1760's.
John does appear to have had some sons who were older than James (1790), Isaac (1793) and Eli (c.1800), because he already had four sons in 1790. I haven't found any trace of the "missing" sons, which isn't all that surprising, considering how people were moving around in those days.
Based on dates and naming patterns, I think that Roane County bunch is related to the other set of Forresters from Greenville and Spartanburg counties. But their recordsdon't show a set of parents with both a Thomas and a William. Here's the family as reported in The History of Roane County:
1. Marcus, of South Carolina. Said to have been a soldier in the Black Hawk War, but I'm not sure about this since he would have been well into his 50's, if not older, at the time. One source says his wife's name was Deborah, but I haven't been able to confirm this. Actually, I have a hunch that this was Mark Forrester of Greenville County, who was probably born in the 1750's, and that the Roane County children were the children of a second wife. But it's only a hunch, based on some circumstantial evidence that may or may not hold up.
2. Children of Marcus:
Thomas, m. Peggy Marney. Only son listed isSolomon.
Alexander, m. Sallie Harvie. Sons William, George, Marshall H. and James, daughters Nancy and Eliza. Was still in Roane County in 1860.
Solomon, born 1803 in SC, died 1863. Married Sarah Marney in 1852. Sons Rufus, James, Joseph Bryant, William, Alexander, Robert, Benjamin Franklin, daughters Caroline, Polly Ann, Martha, Belinda.
James, married Patsy Bryant. Daughters Polly, Bettie, Nancy, Jane, Deborah, Maria.
Larkin, married a Tuton. Sons Wiley and Thomas, daughters Minerva and Rachel.
Of this list, James and Solomon had moved to Crawford County, Arkansas by 1830. Alexander, as I said, stayed in Roane County. I'm assuming the Thomas on this list is either the Thomas Sr. or the Thomas Jr. that you referred to in your e-mail to me a few weeks ago (sorry; I'm really, really backed up!).
This Roane County lineage doesn't really look all that complete to me, so it's possible some of the descendants who left the county early are missing.
I can't absolutely confirm that the head of the Lincoln County family was John Forrester of Spartanburg County, by the way. It's just that all the clues are pointing me in that direction. The Forresters are maddening to research because there were so many different families following the same well-worn migration paths.
And, by the way, I've never found a William Forrester in Spartanburg or Greenville County records.
Sorry. I'm rambling. It's late. I'm signing off now. I hope this has helped you, rather than confusing you further.