It's still not possible to return to the way things were.
After all, the event task set by the system is named "Unfinished Business with the Ghost," not "Unfulfilled Love with the Ghost".
From the beginning, Liu Yun's main aim in persuading was not to make Li Mochou forgive Lu Zhanyuan. Rather than being about women, unworthy men are the common enemy of all men.
Furthermore, Lu Zhanyuan had already died, and his corpse had completely decayed. Even the vultures wouldn't touch what was left of him after the Sky Burial. If he had a romantic tragedy together with Li Mochou, who had just reconciled with him, after the event was over, that'd cause a whole lot of trouble for Liu Yun.
For Ye Weiming, naturally, that is also not an acceptable outcome.
Rather than letting Li Mochou die from unrequited love, it would be better for him to take action and send the other person on their way.