I always freeze my cakes. What I do is let the cakes cool for about 5-10 min in the pan and then flip them out and wrap them in saran wrap immediately. I wrap very well and then place on top of a cake board and place in the freezer. When I am ready to use the cakes I bring out about a couple hours and place in the counter to defrost. When they are defrosting I do not remove the saran wrap. The saran wrap will be wet from the moisture and I simply wipe dry…again while they are still wrapped. When they have been thawed out I then do my normal cake prepping procedures.
As far as the cupcakes I always bake them fresh. However, for samples I like to freeze my cupcakes. What I do is let them cool slightly and then I place them in a large freezer ziplock bag. When I want I want to use them…I take the bag out and either 1) let them thaw out in the bag or 2) you can take them out and let them come to room temp. Cupcakes are very quick to defrost. About 30 min or so.