I am planning on making a pie for my dad for father's day. I know when you buy most pies at the grocery store, you have to pop it in the oven for a few minutes to heat it up. Is it possible to do a similar thing with a homemade pie - bake the whole pie (not just the crust) most of the way one day, and then finish it off the next? I don't want to fully bake it and then heat it in the oven because I am afraid it will burn or overbake, but I also don't want to underbake it and have it go bad.
I'd avoid the whole reheating issue altogether and simply keep the uncooked pie in the fridge, covered in plastic wrap, then bake it as normal when ready. The only issue you might have is if your filling is very runny, in which case you could par-bake it a little before filling to help it 'seal'.
The butter or shortening should never slowly become warm between the time the crust is mixed to the time the time the pie is finished baking. This is why you use iced water and cold shortening to mix the crust and place the crust after rolling back into the fridge before filling.
Imagine the example of bread. If you have uncooked bread dough and pour water on top of it the water will run down the side and if the water sits in the bowl with the dough only a little will be absorbed into the raw dough. Now if the bread dough is cooked and water is poured onto it the bread will absorb all the water. The same concept is true for pie dough that is about to be frozen. The uncooked dough will repel the moister better than partially cooked or fully cooked dough.
Also if the dough is fully covers the filling, the dough has a lot of fat in it which acts like a layer of protection in the freezer. Freezing pies is great at the height of berry season when they can be bought in bulk super cheap to preserve the fruit for when it's cold.
I doubt that if the pie filling is super runny it's a good idea to freeze it, otherwise just having uncooked dough works quite well for freezing pies for later.