So far, the only Mortal Kombat 3 version of Liu Kang I could find for normal MUGEN that is not developed for Mortal Kombat Project full game. Unfortunately, he seems to be a little bit unfinished, as he lacks Fatalities, throws, and a few required sprites.
This character also has alternate .def file which loads his "Zombie" sprites (based on his appearance in Deception and Armageddon) from multiple Mortal Kombat Project-based compilations such as Anthology and Chaotic, but his gameplay remains the same.