Jaycee Cho-Ming Chan, who voices the young Monkey, is the son of Jackie Chan, who voiced Master Monkey in Kung Fu Panda (2008); and James Sie, the voice of Viper's father, is best known in the role of Jackie Chan in Jackie Chan Adventures (2000).
When Po and Shifu are running up to the doors of the palace, Po's names some animals that he thinks they are about to fight. All of the animals he names are bad guys in Kung Fu Panda 2 (2011).
In this short film, it's revealed that Tigress is not only Shifu's student, but she's also his adoptive daughter.