It's so hard to gauge, in my opinion the plot, for this world. On the one hand, like you said, they are worried about being caught with Boo and Mike even seems surprised seeing monsters not afraid of children, but late in the trailer we see the scare floor is indeed the laugh floor. My conclusion?
Maybe the world starts off with the film plot, then eventually takes place after the film? Maybe Randall is a mid boss and Vanitas is the final boss? Man I have no idea (I just better get Randall in this world).