John, I checked the diocese records. Victorine Pourciau and Marie Ciphael Pourciau did in fact have a son named George Pourciau. Born Nov. 15, 1890. So, the George on the 1900 census cannot be George Aguillard.
Ciphael Pourciau & Victor Pourciau were indeed 2nd cousins, and were married April 20, 1891. (after the birth of your George)