what are 1/8 Amerindian + 7/8 Spanish (or other caucasian) people called ?
For the most part, someone who is 7/8 Spanish & 1/8 were classified as Criollos Espanoles, or in other words Criollos de Vuelta.

But it also depended on phenotype, if a Castizo & a full-blooded Spaniard had a child that looked Castizo, then that child would be classified as Castizo.
If you see the article of the Pobladores of Los Angeles in the 1793 Census of New Spain, many of the children of Spaniards & Mestizos were classified as Spaniards, usually because their Mestizo parent was usually either Harnizo or Castizo, while the children of Mestizos & Spaniards that were classified as Mestizos, because the Mestizo parent was usually a Balanced Mestizo.
https://en.wikipedia.org/wiki/Los_Angeles_Pobladores
If you see my thread on here about the DNA results of 7/8 White & 1/8 Amerindian, you will notice that most of them look fully or nearly fully white, but some of them look Castizo as well.
https://www.anthroworldforum.com/th...omolos-also-known-as-criollos-de-vuelta.2608/
For example, I'm Harnizo, & my wife is fully European, our children will be around 7/8 White & 1/8 Amerindian, very likely they will look fully or nearly White, but there are good chances that they might come out looking Castizo as well.