If you make a cake and freeze it then carve, ice in buttercream and add all of the fondant accents like a diamond pattern around the cake, will I have a problem freezing the cake again? I've never re-frozen a cake and have never frozen fondant. My problem is the cake is for Saturday, it will be a big one, but I have so much going on Thursday and Friday that tomorrow is really my only day that I can do this.
Thank you for your advice with this.

you won't need to re-freeze it, as long as you have put some kind of icing on it to seal in the moisture, just leave it out. Most cakes will last up to a week, as long as they are sealed. Make sure you use simple syrup to keep it moist.