While the scene is humorous, when you look deeper there are some key features that are very accurate to Chinese ancestor worship practices.
The first thing to note are the tablets. Each ancestor has a tablet on which their name may be inscribed, similar to the headstones we use in Western culture. However, these tablets would be brought together at a family altar. This is what we are seeing in the Mulan clip--the ancestor tablets within a family altar. Each tablet contains a part of the soul, which they termed the hun. (1) Below is an image of an actual ancestor tablet, from the Anthropology Museum at the University of Missouri.
Translation: "Spirit tablet of the illustrious Lord Zhang, who had received the title of Grand Master for Governance from the Qing court Respectfully set up by his pious son, Zhang fujun." http://anthromuseum.missouri.edu/minigalleries/chinesespirittablets/1983-0073-tablet.shtml |
Unfortunately, the Cultural Revolution under the Communists purged much of the ancestor worship from China. Many tablets were destroyed in the process of the revolution, and now very few continue to practice ancestor worship. Those that do use scrolls and photographs, unless they were one of the villages that managed to avoid having their tablets destroyed. Most practice in secret as well. (3)
(1) "Settling the Dead: Funerals, Memorials, and Beliefs Concerning the Afterlife," last modified in 2007, http://afe.easia.columbia.edu/cosmos/prb/journey.htm#fn
(2) Myron L. Cohen, "Religion in a State Society: China" in Asia: Case Studies in the Social Sciences, ed. Myron L. Cohen (Armonk, NY: M.E. Sharpe, 1992), 10.
(3) Stephen F. Teiser, "The Spirits of Chinese Religion" in Religions of China in Practice, ed. Donald S. Lopez, Jr. (Princeton, Princeton University Press, 1996), 23-24.