If you get the baking powder wet, it'll do its thing (or half if you have double action). The eggs can turn weird too. Can you assemble kits? Stir together all the dry ingredients and seal them in a ziploc, or just a covered mixing bowl since you'll be baking tomorrow. Measure out the wet ingredients individually in jars, and put the jars for a single recipe in an open container to keep them together, along with the whole eggs. Or maybe just use a food marker, or a piece of tape, to label each egg as to which batter it goes in so they're easy to grab. You could color code each recipe so you don't have to read the labels.

Freezing is different than chilling. If you refrigerate the cakes, they could get tough. Cold causes the starches to tighten, which is what "stale" means. Better to make cakes that can be frozen a couple of days ahead and freeze them (freezing should suspend the starches rather than tightening them, plus cakes can be softer and fluffier after freezing), than closer to the day and refrigerate them.

Good luck! That's an ambitious load, but it sounds delicious!

Ruthanna's apple cake freezes beautifully. I make it without frosting as our family does not like frosting. It is delicious and very moist.