As to the question of the identity of J. D. Pulliam, associate of Jackman, I am virtually certain that he is son of Benjamin J. Pulliam of Howard County and grandson of Drury Pulliam of Saline County, as I stated in my book Other Noted Guerrillas, and that his given name is James Drury rather than John Drury. On one of the Individual Military Records of Confederate Soldiers for Pulliam (it appears to be, based on written notes I took at the time of my research, to be Microfilm Reel M322, #137 at the National Archives in KC) Caldwell County, Texas is given as the soldier's place of residence at the time of his enlistment. On this same record, his nativity is given as Howard County, Mo. In the 1860 Caldwell County census, we find James Pulliam, age 19, listed as eldest child in the family of B. J. Pulliam. The birthplace for all the children ages 19 to 10 is listed as Missouri. Only the youngest, age 8, was born in Texas. J. D. Pulliam's age at enlistment in 1862 is given as 22. It's obvious from other information in the military record (connection to Waldo Johnson, etc.) that this is the man who was later associated with Jackman. From the man's age and his connection to Caldwell County, Tx., it is also obvious that the man who was listed in household of B. J. Pulliam is the same man as that of the military record.
I have been wrong before. For instance, based on a misleading newspaper article, I confused Mart Ryder's uncle with his father in my Other Noted Guerrillas book. So, I rarely say that I'm 100% sure of any factual information, but I'm pretty sure in this case.
As to the question of whether J. Drury Pulliam actually was killed in 1864 as Jackman said in his report, I don't know, but I tend to accept Jackman's report at face value.