Hi Tony,
You mention that your great grandfather Rosales had married a native woman from Chimaltenango. Do you know his name? That helps explain my results from 23+Me: I learned that I'm about 4% Native American. The Rosales Alcántaras tend to look pretty dark, and I thought that might have come from North Africa, but I'm only 0.1% North African (and 0.1% Ashkenazi). I'd like to see your family tree going back before the Flores Alejos.
Here are a couple of photos including Berta Rosales de Mendoza and perhaps other members of your family, taken at the Chalet San Buenaventura, my grandparent's home in Guatemala City.
Best Wishes,
-Stephan