I will be delivering a cake around noon Sunday. Ordinarily I'd cover with fondant/ decorate on Saturday, fill and crumb coat on Friday so it can settle. This time I've actually baked a week in advance and frozen the layers. Can I move my schedule up at all so I'm not rushing on Saturday? Could I fill/crumb on Thursday and start decorating on Friday? Or will my cake not be fresh if I do this? I dont want it to dry out for Sunday, and would ideally like any leftovers to still be tasty as well!

Is your cake a scratch or box recipe?

one tier is the scratch WASC recipe, the other is a scratch chocolate cake make with oil.

I would think you can fill/crumb on Friday evening and have everything ready to decorate on Saturday.  This usually works for me, but I add my final layer of frosting on the Friday as well.

Do you use simple syrup? If you don't currently use it, it makes a huge difference in how moist the cake stays, especially if you are making them ahead. I always use it.