What has happened to all the Taiwanese citizens that the PRC claims to have evacuated from Libya?

It wasn't a farce. Air China granted each of them a free flight home. As the aircraft approached Taiwan, the PRC citizens on board slapped name tags on each of them reading "Traitor to China", the crew slowed the plane, opened the aft door, and pushed them out. Anything more would have been considered a waste of China's time, energy, and resources. Unfortunately, the ROC's own Electronic Warfare Defense System had been jamming the unidentified plane's radar, and the Taiwanese were dropped over Luzon in the Philippine Islands. Hence, they were never reported as having arrived in Taiwan.