The events in Kingdom of the Sun happened before Emporer's New GrooveSo hear me out, in his youth, Pacha looked a like like Kuzco's dead dad, Manco. Yzma was somewhat younger and still vain, and the pretty boy lackey was the previous model before Kronk. Yzma's father being the Grand Mortician allowed her to stay alive much longer than she other wise should have, and some act of heroic forgiveness on Manco's part forgave Yzma of her crimes, an action he would not live to regret. Manco died and Yzma ruled in his stead, raising Kuzco.
Kuzco is left handed.The arm he has to use later is his left. He also does the kiss stamping thing with his left.