As far as the official beef contractor for the state, that would be George W. White, at least for the earlier part of the war. He might have agents buying up cattle but he was not in the military himself.
Could Scott have been an agent for the meat packing plant in Jefferson? I have a copy of the thick book on the port of Jefferson at home, and if I can dig it out I'll check for Scott. It might be William Thomas Scott of Scottsville, Harrison County (see Handbook of Texas), a plantation owner who also was part-owner of the very short pre-war railroad in that area. He might have also had an interest in beef-packing. It's worth a look.
Vicki Betts