The SC Memory Rolls say the following about your three ancestors in the 26th:

Co. A - Asa G. Causey - age 30 - Pvt - Surrendered Appomattox

Co. E - Daniel W. Brown - age 35 - Pvt - Horry District - discharged or surrendered at Charleston - Living

Co. E - Bentley S. Stalvey - age 32 - Lieutenant - Horry District - Living

ALSO LISTED IN COMPANY E (possible relatives):
Richard Brown - age 30 - Pvt - Horry District - died at Point Lookout Prison
Nelson A. Brown - age 36 - Pvt - Horry District - discharged or surrendered at Charleston - Living
Mayberry Stalvey - age 25 - Horry District - Killed at Secessionville
Andrew J. Stalvey - age 23 - Pvt - Horry District - Living
Henry Stalvey - age 20 - Pvt - Horry District - Killed at Jackson, Miss.

The Memory Rolls were compiled by the SC Confederate Historian in the 1890s with the assistance of survivors, thus "Living" means that the man was still alive at that time to their knowledge.

Except for the 1904 memoirs of Lt. Col. Hudson, the only history of the 26th is my book, Wandering to Glory: Confederate Veterans Remember Evans' Brigade (USC Press, 2002).