Yes!
Wang Yunxiao actually thought the same, "Why would you arrange a ghost marriage now when you can do it any other time?" He also vaguely remembered hearing from Third Master Ding that there were many nuances to arranging ghost marriages, the most taboo of which was forcing living people into ghost unions, which easily conjured fierce ghosts. So, unless they bore a grudge against the family, or intended harm, people generally didn't engage in such acts.
He had seen what fierce ghosts looked like and knew they indeed existed.
So, when he saw the young bride in that sedan, he felt there was something fishy. Now, seeing the genuinely baffled expression on Third Master Ding's face confirmed his suspicions.
The use of the Mealybug Doll was indeed a spell known to Third Master Ding, but he wasn't the only one skilled in trickery here; someone guilty had already fled.