Marisbury wouldn't have had to predict everything CHALDEAS was doing. In fact, if he had, most of this game probably wouldn't have occured.
Marisbury did not have to predict that Olga would be thrown into CHALDEAS, or that his A team would all be killed by Lev. He intended to use them to fulfill his goals, but his plan hit a roadblock. He just got lucky that one rando Master survived and was capable of fulfilling his plans as a member of Chaldea.
Marisbury did not have to predict that the Lostbelts would occur. We act independently to resolve the Lostbelts, and the fact that doing so removes obstacles to Marisbury's plan is a (for him) happy coincidence. Even the Chaldean thought that we were knowingly trying to enact Marisbury's plan, when we don't even know what his plan is. And when we do get an inkling of what's going on, we reject it.