You forgot the first step, where they were coerced into Catholicism by conquering armies of frenchmen and spaniards.
I thought that was implied by the inclusion of the religion-hybrid phrase.
The armies as such had very little interest in that, and the Aztecs even less.
By 1531, after several decades of Spanish domination there were very few -- perhaps a hundred or less -- indigenous Catholic converts in Mexico. But by 20 years after that, they numbered in the millions.
What made the difference? Nuestra Señora de Guadalupe.