I am not well versed in the Masonic History, but I believe that there were two Masonic Lodges in the Pine Bluff area, the Jacob Brump Lodge and the White Sulphur Springs Lodge. Both lodges are still in existance.
Pine Bluff in 1860 was one of the larger cities in the State at a population of 1,200. But it also was an important crossroads community and commercial district for the shipping of good east and recieveing of goods by river and road.
I think one of the men that is being overlooked here in this Pine Bluff connection that you mentioned was a very powerful politician that you mentioned before, Robert Johnson.
Johnson lived in Pine Bluff and was a Senator to the Confederate Congress and I am not sure but may had been a United States Senator before that. He was given the rank of Colonel. And was the enlisting officer at Pine Bluff for a while in 1862, and may have been active in the formation of the early units from the Pine Bluff area in 1861.
So it is not hard for me to see both Thompson and Bronaugh being associated on a personal level with men like Johnson and Roane from Pine Bluff.
According to muster roll records over 2,000 men in 23 different Infantry and Cavalry Companys and Artillery batterys enlisted in the Confederate Army from Jefferson County during the War. This figure is not to be confused with, nor does it include companies which were enlisted in other counties and then came to Pine Bluff to be organized.
In 1861 Jefferson County and Southeastern Arkansas was some of the stronger supporters of secession. Militias at Pine Bluff had participated in the siezing of the Arsenal at Little Rock and had stopped Steamboats carring supplies to the US garrison at Fort Smith.
So it is quite easy to see how Pine Bluff would have been seen as an area ripe for the harvest of men willing to join for the fight. It is a mistake to assume that Little Rock was the end all and be all of politics in Arkansas. Little Rock was NOT the center of the Universe of such affairs in the State of Arkansas in 1861 as it is today.