Fun fact: Tenochtitlan fell in 1521. From 1603 onwards, large numbers of honest-to-god fricking Japanese Samurai came to Mexico from Japan to work as guardsmen and mercenaries. 

Ergo, it would be 100% historically accurate to write a story starring a quartet consisting of the child or grandchild of Aztec Noblemen, an escaped African slave, a Spanish Jew fleeing the Inquisition (which was relaxed in Mexico in 1606, for a time) and a Katana-wielding Samurai in Colonial Mexico.

Also a whole bunch of Chinese Characters BECAUSE MEXICO CITY HAD A CHINATOWN WITHIN TEN YEARS OF THE FALL OF THE AZTEC EMPIRE.