Canned pastry/pie filling?

If you are baking the filling inside the cupcakes it should be okay to sit out overnight.

If you are filling them after they are cooked, you risk the fruit souring and giving someone a tummy ache. They have the label advice on there for a good reason.

Could you possibly get up early and fill them the morning you need them to avoid any possible problems?

Err on the side of caution if you plan to share these goodies with anyone else

No, the label means to refridgerate the remaining contents of the can after you open the can. Sometimes, people don't use the whole can. They fill what they need and then they still have some left in the can -THAT is what you need to refridgerate (but take it out of the can, put into a bowl). Putting the can itself into the fridge will poison the food.

As for the ones that you put into the pie shells, after baking they are perfectly fine to stay on the counter. Baking them does something to the atoms in the pie filling, where it now no longer needs to be refridgerated.

It depends on what the instructions on the can tell you to do. They will advise you correctly and safely. I believe it might be best to refrigerate so there's no one getting a case of food poisoning. You can always eat something out of the fridge and make space? Or if you have a cooler, put some ice in it and your cupcakes (well covered) and on some sort of divider like a plate or pan so the ice has no chance of soaking the desserts as it melts, then you can be sure someone won't get sick from your kitchen. It's not worth taking a chance.

Naw - all that sugar. The only think I worry about refrigerating is chicken, meat, and fish. When I grew up my mom didn't refrigerate ketchup, jelly, even some cheeses... never killed anybody.