TTJ could only learn to feel in a dream. The first one was the nightmare. He could only dream after entering the maid's dream. After that, he also shed a tears.
Regarding Ming Ye, I know TTJ was not MY's reincarnation in the book, but I won't completely rule out the possibility for the drama version.
The dream arc is even more important in the drama, because the 12 gods actually took an active part in preventing the rise of the next demon god.
My theory is that TTJ really had MY's face (probably just to troll him). Due to this and how SJ turned into a demon, MY made an arrangement to prevent a BE for this version of himself.
Ji Ze and Chun Huang probably even know more than MY.