Santa Ana certainly was, as was almost all of his officer corps. The poor grunts he and his tyrannical officers pushed around--probably a lot of native blood in there, who knows. The mostly "pure" Spanish descendants and Mexican Creoles (both very White) ran the show in Mexico.
Juarez, etc. came along much later.
At UT, a Mexican National student and I had many interesting talks about such history. He claimed that Santa Ana's arch-conservative (as in a classical monarchist/conservative) party was related to the party of the Inquisition (yes, that Inquisition). Then later on in history, the Mexican revolutionaries became the PRI (semi-socialist, anti-clerical/anti-Catholic, modernist), while the party of the Inquisition mostly morphed into the PAN (pro-business, pro-Catholic, traditional). PAN=wealthy mostly-White Mexico City types + Monterrey industrialists + big landowners + Catholic Church. PRI=left-leaning, populist, and extremely corrupt. That's what I learned from him anyway.