The William H. Givens who served in Co. G 10th Tex Inf - Nelson's Regt. applied for a Confederate pension in Oklahoma in 1915, and died in Oklahoma in 1925. The Compiled Service Record mentions this pension application (page 15). Also, as you noted, he is ten years younger than the man who was living in Mobile with three small children in 1860 and who died in Houston, Texas in 1903.

The 38-page record for "William M. Given" in Co E, 2nd Alabama Light Artillery includes two pages with his signature -- pages 33 and 36. On page 33 the name is "Pvt. W. H. Givens" at the top. The signature can be read as either W M H Givens or Wm H Givens. On page 36 the name is "Pvt. Wm. Givins" at the top. The signature can be read as either W M Givens or Wm Givens. The two pages cover the period Sep-Dec 1863, for which he is paid $12/mo. That seems to conflict with page 25, which shows him paid $2.40 (per day assumed) for the 31 days of October 1863. As you noted, several cards in 1863 and 1864 show him paid $3.00 per day as a carpenter. It certainly appears that this is the William Givens seen in Mobile, Alabama in the 1860 census and 1861 city directory. The only remaining question for me is, Why was he dropped from the roll in May 1864? Was it because he was detached to the Engineering Dept?