Don't forget Anna Mae Whittle's "History of Henley, Cole County, Missouri." She names names and unit numbers that so far have worked out, Crabtree, Hoskins, Loethen, etc. Cole County Historical Society does have a listing of LP Crabtree as Lt. in MSG under MacKenzie. MacKenzie went to California during the gold rush returning to Cole county in 1857 or 58. He was killed at Carthage. He was tight with M Parsons during the Mexican War. There is a Crabtree listed in the wounded at Wilson's Creek but I've found it to be a dead end at this stage, I can't seem to get an initial or definitive unit other than 3rd Division MSG which kind of fits.
Following that lead I went looking in census roles for an LP or LC Crabtree in California in 1840, 50, and 60. There is a fellow listed as LC Crabtree in Monroeville, California in 1860 and Yuba in 1850. This is not exactly where MacKenzie was, but is in the neighborhood ergo 50 miles or so. Can't tie the two together at this stage but I've had no luck coming up with a Crabtree in Cole, Miller, or Chariton Co. that fits. There is one in Dent County that I tracked through the war and into the 1880's. I haven't looked into a LG Crabtree but I don't remember that as a common combination popping up in my other search.
Anna Mae Whittle states pretty definitively that Crabtree was buried in "old Bethel Cemetery". She further elucidates "In 1860 a log church was built northeast of Hickory Hill, which now lies between Old Route 54 and the county road near the Curtis Bush home. Daniel Green, a Kentuckian, was the first minister." She claims verbal history from Adolph Loethen's grandson as her source. So next time I go to the Lake I will take a side trip and go cemetery hunting, who knows what might or might not be found.