I want to bake and carve a marble nerf gun cake with ganach as a filling and crumb coat for the fondant. For the base I saw a cake mix with pudding recipe. I want to use that for two 12by 9 pan ,one vanilla and one chocolate to mix to make marble. Chocolate ganache for filling and crumb coat but I’m slightly concerned it’s going to be hard in the fridge because it has cream. I know fondant can be made ahead of time but I heard it’s an issue if it’s in the fridge. So can I bake ,carve , fill and crumb coat in the fridge without drying out? With ganache? Same consistency ok? And the fondant?