The metal is from Elite miniatures except for the Sapper and Fifer who are from Front Rank.

Here is some info on the unit:

Organisation
The Corps of Texas Spanish Tercios (Tercios Españoles de Tejas) hereafter referred to as the Tercios de Tejas was an expeditionary corps raised in Spain by Brigadier don Pedro Grimarest starting 6 August 1804 being destined for the province of Texas. However in 1808 it still remained in the Peninsula located at Cadiz. They never reached Texas.
The Tercios de Tejas were to made up of four light infantry and four cavalry tercios, each of 3 companies. It was actually formed as two light infantry battalion-like tercios and (probably) two cavalry squadron-like tercios.
The infantry were in combat at Menjibar on 16th July 1808 and Bailen on 19th July 1808 with a strength of 436 men as part of Lt General Teodoro Reding's 1st Division. On 12th August 1808 one tercio was converted to the Batallon de Cazadores de Bailen and the other to Batallon de Cazadores de Las Navas de Tolosa.
The cavalry served at Uclés on 13th January 1809 with a strength of 15 officers and 153 troopers. They were later renamed the Cazadores de Sevilla.

28mm Napoleonic Tercios Españoles de Tejas