Pat, it has been a long time since this thread began, but I just started researching the Izards (my husband's family.) I hope you are still checking this forum.
George Henry's dad was John G. Izard and they can be found on 1850, 1860 and 1870 census in Fayette and Lavaca County, Texas. 1880 he is listed as J. G. in Waller, Texas. I picked up a lot of information from your early posting that verifies and adds to what I have.My husband's dad was Roy Preston Izard, son of Silas Preston (Dawes Rolls) who was George Henry's son.I have lots of names of descendents if you are still working on this.