I'd be really surprised if Rick didn't find some of these fake candies with how thoroughly he'll be searching, so definitely opting in here! As for replacing the candy he's already gathered, he wouldn't notice unless he caught Ganondorf in the act--also possible by the last few days (or whenever Rick is no longer able to search), since he'll become paranoid enough that he'll just stay in his room and guard what he's gathered at that point. Is this something Ganon would try to do, or would he find less vigilant prey?