Ok so I started my own cupcake business from my home and I have started to do cakes. So far, all of my cakes have been made the day of but I have an event that I'm doing a 4 tiered cake and 10 dozen cupcakes so I'd like to bake my cakes for Saturday ahead of time without freezing. My questions are: when do I bake them if needed for Saturday evening? I would like to add a syrup to the cakes, do I do this while it's hot or wait until I torte the layers and it's cooled? I'm covering in buttercream and then adding fondant designs. I'd like to add a filling but don't know what would be the best crowd pleaders. I'm doing 2 tiers of vanilla and 2 tiers of chocolate, any suggestions or help would be great! Thanks!

I would bake on Thursday.
As for fillings, if they want buttercream icing, you can't go wrong filling with buttercream as well. If you want something different I would search through the most popular filling recipies here. Jam or fruit based filling are usually quite well liked with most people.