Here is an " a-ha" moment. William F. Post of Galesburg, Illinois, and James B. Post of Sidney, Champaign county, Illinois, enlisted on the same date in Sidney, were mustered into the same unit a few days later in Chicago, and both for 3 month terms. William was listed as a brakeman, while James was listed as a butcher, both born in New York, nearly identical physical descriptions. William enlisted as a Corporal, and James as a Sergeant - they knew someone?
James B. Post:http://www.ilsos.gov/isaveterans/civilMusterSearch.do?key=20...
William F. Post:http://www.ilsos.gov/isaveterans/civilMusterSearch.do?key=20...
Monmouth papers mentioned daughter of James and daughter of John to be cousins.
Monmouth papers mentioned John's ex-wife and daughter attended funeral for "her" brother, William F. Post; that was actually John's brother.
1870 census - William (F.) Post is living in Galesburg with the families of Mrs. Adam (Hannah Post) Eason and Mrs. Elizabeth (Post) Sly, widow of Charles Lewis Sly. Both of these women are widowed by 1880, and still living together in Galesburg with their children. Very few traces of them found after this record.
From this, I would say that John J., James B., William F., Elizabeth, and Hannah were siblings. There seems to be at least two branches of the Post family in Galesburg, as mentioned in the Post-Post marriage. I believe one branch was descendants of William Townsend Post, and I seem to recall that his son Edward was one of the first residents of Galesburg (named for Rev. George Washington Gale, who brought his "flock" from New York to start their own "colony"). I think the wife of P.S. Post Sr. was also the daughter of that Wm. T. Post. I'll try to see next weekend if I can get to the Galesburg library and dig something up. Perhaps the Galesburg papers actually named William's parents in his obit. He was buried in Hope Cemetery, where the only other Posts were Gen. P.S. Post and his Post wife, along with P.S. Post Jr., and his wife.
Post Phillip Sidney 19 Mar 1833 - 5 Jan 1895
Post Cornelia Almira 30 Jun 1844 - 25 May 1908
Post Phillip S. , Jr. 10 Nov 1869 - 27 Jun 1920
Post Jane Greig 21 Nov 1871 - 24 Jan 1964
Post William F. 1843 - 1901
(Records do show August Miller Post was also buried here, perhaps without a marker).
Anyway, it's late here and I need to get to bed. I hope the fires are under control there. I saw some in some footage aired last weekend on an amateur radio program on YouTube.