Yes, Yan Tang should be his courtesy name and called only by family members or those closed to him. Still I haven’t heard FL call him ST. Sang Mo should be his official name, how the general public addressed him.
the slapping scene, I wonder if jiyong also rebirth from the past🤔
I think yes. He hinted FL when they were eating ice cream. “You know, I Know”. He said he will go with the flow and if the Crown Prince will revolt then it will align with his initial plan. But she didn’t ask any follow up after he said it, and just brush it off.