More tidbits:

Name: Frank M. Grace Rank: Private Company: E Enlisted July 9, 1862 Denton Co. TX
Served mostly in or near Sabine Pass and Beaumont area.
Discharged August 1865

treemaker.genealogy.com/users/h/e/n/James-Henderson-VA/WEBSITE-0001/UHP-Sources.html
CONFEDERATE TEXAS TROOPS, John was recruited by Griffin's Texas Infantry that merged into the 21st Regiment, Texas Infantry. The 21st Infantry Regiment was organized during the spring of 1864 by consolidating the 11th (Spaight's) Texas Cavlry and Infantry Battalion and Griffin's Texas Infantry Battalion. Serving in the Trans-Mississippi Department, the unit was stationed at Sabine Pass with 14 officers and 235 men. Later it moved to Louisiana, then returned to Texas. It disbanded prior to the surrender in June, 1865. Its commanders were Colonel Ashley W. Spaight, Lieutenant Colonel William M. Griffin, and Major Felix C. McReynolds.

http://www.slidellbattery.com/
SPAIGHT’S BATTALION HISTORY
Spaight’s 11th Cavalry & Infantry Battalion
The 11th was a mixed command organized with 400 men in April 1862 and served in the Department of Texas, formerly known as the 6th Texas Infantry Battalion it can trace its origins to the “Sabine Pass Guards” Militia formed in 1861. Some of Colonel Ashley Spaight’s Texas Confederate volunteer companies were also known as the “Swamp Angels,” all of which served to defend the Texas gulf coast and Louisiana borders from Federal incursions. The unit was assigned to Hebert’s Brigade in the Trans-Mississippi Department, many of whom lost their lives during the 1862 “Yellow Jack” epidemic at Sabine Pass.
During the spring of 1864 it was merged in the 21st Texan Infantry Regiment, which was a consolidation of the 11th and Griffin’s Texas Infantry Battalion. Serving in the Trans-Mississippi Department the unit was stationed at Sabine Pass. The unit now consisted of 14 officers and 235 men. Later the unit moved into parts of Louisiana returning again to Texas and disbanding in June of 1865.
These battalions was comprised of mostly southeast Texas residents, many of whom became community and business leaders after the war.
Spring 1862: Commander LtCol Ashley W Spaight and Major J S Irvine
Spring 1864: Commander Colonel Ashley W Spaight, LtCol William M Griffin, and Major Felix C. McReynolds

For more info on Spaight’s Battalion, refer to the East Texas Journal, XXX, No.1 (1992)

Spaight’s Battalion had seen more combat than any of the other Confederate units in the Battle of Calcasieu Pass. Because of its discipline and good order it had earned the nickname, “Swamp Angels.” Raised in the Beaumont area, the battalion was commanded by Lt. Col. Ashley W. Spaight, who during the battle was with Company F to safeguard Confederate cotton and blockade-runners at Lake Charles. The battalion had fought in the first Battle of Sabine Pass, Sept. 24-25, 1862,
the high seas capture of two Union gunboats on Jan. 21, 1863,
the Battle of Bayou Fordoche, La. Sept. 29, 1863,
and the Battle of Bayou Bourbeau Nov. 3, 1863
before the Battle of Calcasieu Pass.
Companies A, C, D and E of Spaight’s Battalion fought in the Battle of Calcasieu Pass.