Making a cake for turkey day it's going to have 4 layers if I made the cakes on wenseday night and wrapped them up in Plastic wrap would they be ok to frost and decorate the next day?

i am filling them with chocolate mouse I got the instant kind (no time to make from scratch) do I need to make a buttercream circle around the layers to hold in the filling and so that the cakes stay or can I just add extra flling.  (First time ever filling a cake) 

also should I fridge the cake before icing it or should I dirty ice it fridge then ice and smooth out the layers before I decorate the tops doing the colors of candy corn in a star tip around the top of the cake 

Yes to all of it:  Baking and wrapping Weds, buttercream dam to hold in the filling, you don't need to fridge before filling but after filling and crumb coating would be a good idea.