Was Ygnacio Garcia from San Jose the last Genizaro? Let us look at the record(s) available and see. Above is an image from the 1860 U.S. Federal Census for San Jose, New Mexico. Refer to and enlarge the bottom portion of the image to see the name in question, Ygnacio Garcia. It clearly states that him and 3 others are living in the Prudencio Lopez household as "servants".
Genizaros were detribalized non Pueblo Indians in the midst of Hispano society in New Mexico before the American occupation in 1846. And there were many of them. The Comanche, Navajo, Ute and Apache would, in the course of their raiding, take captives. Young boys and women for the most part. The Spanish in New Mexico in time came to purchase these detribalized Indians. They did it to acquire servants, they did it to convert them to the Catholic faith and, in some cases, they did it to save their lives. Needless to say, New Mexican Hispanics raided Native American tribes and took captives also.
The marriage record for Ygnacio Garcia at the San Miguel del Bado Church in San Miguel del Bado, New Mexico states that on October 26, 1863 "Ygnacio Garcia, captive and servant of Prudencio Lopez, of San Jose married Petra Vigil the daughter of Ramon Vigil and Maria Dolores Ulibarri of San Jose. The witnesses to the marriage were Luis Maria Martín and Andres Martín."
The 1860 U.S. Federal Census would not state that he was a captive because it was illegal to have captives. There is no way that Prudencio Lopez was going to tell the enumerator that he had captives and used them as servants. But the priest documenting the marriage must have known about Ygnacio Garcia, not only his status in the Lopez household, but his origins as well.
And as such the origins and status of Ygnacio Garcia come down to us in the historical record.