I don't know, the whole Big Mom children are keeping a secret the things she did seems kinda weak considering that she has no qualms in sending assassins after her daughter. Or having to kill Perospero if he lied.
The scene with Mont D'or can serve to show that Moscato might come back later, but it could also just be that they were collecting his soul because of the worth it has in Tottoland. They basically got a lump deposit. Not to mention that it really didn't seem to affect any of the Big Mom Pirates afterwards at all. They were: "see, not even Mama's children are safe" and brushed it off as a regular occurrence. It could be, that like Smoothie, they didn't want to hold a funeral, or say anything about it to not upset Mama before the wedding. But, I like to believe that if faced with the truth, Mama would reply: "He should have not gotten in my way if he didn't have my request".