I have stacked and iced my cakes. Do I keep them wrapped in plastic wrap and in freezer until I'm ready to cover in fondant?When I defrost them do I wait till they are completely thawed before covering fondant?

You do not want to cover a cake with fondant that is frozen- thaw the cake- when you are ready to cover pop it in the freezer for a few minutes- maybe 10-15 tops- just enough to harden up your buttercream or ganache- then cover-

I believe if you cover a frozen cake with fondant- condensation occurs under the fondant and blow-outs are likely-

Mo

You SIMPLY MUST wait till the cake is thawed before applying fondant. That it's already iced is a huge bonus. Applying fondant to cold cake causes condensation and you get a sticky, icky possibly runny fondant.

So after you fondant the cake do you place it in the fridge?

Most people will apply fondant before stacking.

I meant I have stacked the layers of the tiers. I have not applied fondant yet. I will before I stack the tiers. Hope that makes sense. I just am not sure when is the best time and temp to apply fondant. I am using fondx fondant, can this be refrigerated after I put it on the cake?

Once a cake is sealed with fondant, it's fine left out - - of course, depending on how long until delivery/pickup. Some people refrigerate ALL cakes. I don't cover with fondant/modeling chocolate until just before time to deliver, so nothing with fondant goes into the fridge.

When you chill or freeze a cake with fondant, you run the risk of condensation either making it gooey or making the colors run or both, especially if it's not properly boxed and wrapped.

If you must chill or freeze the cake after the fondant goes on, be sure it's boxed and double-wrapped with plastic. Bring it back to room temperature with the wrapping still on, so any condensation will be on the wrapping, not the fondant. HTH

If I cover the cake in fondant Thursday evening will it be OK at room temp to deliver Friday evening?

It should be fine. Sugar is a preservative and the fondant will seal everything so there shouldn't be a problem.