SOUTH CAROLINA CONFEDERATE SOLDIERS, 1861-1865, Janet B. Hewitt, ed., (Broadfoot Publishing, Wilmington, NC: 1998), lists the following men in Co. E, 8th SC Infantry:
PVT Nelson KERBY
PVT Hampton T. KIRBY.

The following men are listed in Co. C (Culpepper's Battery/Wilson Light Arty.), 3d (Palmetto) Bn. SC Light Artillery (hereafter, PBLA):
PVT Isaiah KIRBY
PVT J. P. KIRBY
PVT J. R. KIRBY
CPL John M. KIRBY
PVT Mahoney KIRBY
SGT N. S. KIRBY
PVT W. M. KIRBY
PVT William KIRBY
PVT William J. KIRBY

BROKEN FORTUNES: SOUTH CAROLINA DEAD IN CSA SERVICE 1861-1865, by Randolph W. Kirkland, Jr., (SC Historical Society, Charleston, SC: 1995), lists only two of the above names:
PVT H. KIRBY, Co. E, 8th SC Infantry, Darlington Dist., died of disease at Richmond, VA, 16 Apr 1862.
PVT W. J. KIRBY, Culpepper's Battery, died in prison at Ship Island, MS, 24 Dec 1864.

DARK HOURS: SOUTH CAROLINA SOLDIERS, SAILORS AND CITIZENS HELD IN U.S. PRISONS, 1861-1865, by Randolph W. Kirkland, Jr., (SC Historical Society, Charleston, SC: 2002), lists the following:
PVT John M. KIRBY, Co. C, PBLA, captured at Blakely, AL, 9 Apr 1865, and sent to Ship Island, MS. Moved to Vicksburg, MS, for exchange, 2 May 1865. Paroled at Augusta, GA, 20 May 1865.
PVT W. M. KIRBY, Co. C, PBLA, captured at Ft. Gaines, AL, 8 Aug 1864. Exchanged at Ship Island, MS, 4 Jan 1865.
PVT William KIRBY, Co. C, PBLA, captured at Blakely, AL, 9 Apr 1865, and sent to Ship Island, MS. Moved to Vicksburg, MS, for exchange, 1 May 1865. Paroled at Augusta, GA, 20 May 1865.
PVT William J. KIRBY, Co. C, PBLA, captured at Ft. Gaines, AL, 8 Aug 1864. Died of dysentery at Ship Island, MS, 24 Dec 1864.

For more information on any of these men, suggest you obtain copies of their Compiled Service Records from either the SC Archives (http://www.state.sc.us/scdah/homepage.htm), or the National Archives (http://www.archives.gov/research_room/obtain_copies/veterans_service_records.html).

Hope this helps a little.