In terms of actual drawings of military actions down along the coast, there is a drawing of the Battle of Port Lavaca (the only one I know of) in my new book, The Southern Journey of a Civil War Marine. There is also a drawing of a December 29, 1863 skirmish on Matagorda Peninsula involving the 13th Maine and Texas Cavalry on page 106 of my Sabine Pass book. Finally, there is a great article by Norman Delaney in the Southwestern Historical Quarterly that has several depictions of the Battle of Corpus Christi.Volume 108, No. 3 January, 2005 "Searching for Sergeant Gambel: David Reed Gambel, Soldier and Painter, 1825–1874." Hope this helps.