Thank You: Pre-making Thanksgiving foods

On the stuffing question, you could do the cooking part ahead and refrigerate those ingredients, but I wouldn't recommend actually mixing them together with your bread product until just before baking it. I think it would be too soggy otherwise (but not harmful -- the reason not to stuff a turkey the day before is because of the uncooked turkey juices filtering into the stuffing -- that's what makes people sick).

On the mashed potatoes, I've had a couple occasions where I've cooked them the day before, mashed with a potato masher, refrigerated them and them done the final preparation the next day by adding the milk & butter to the potatoes (reheated in a microwave) in the mixer bowl.

(In fact, you probably could fully prepare the potatoes the next day and either reheat them in the microwave or tightly covered in the oven for probably 30 min., more or less -- depending upon the quantity of potatoes.)

Vegetables are best prepared freshly before the meal -- but perhaps you could cut them up the night before and refrigerate them in tightly sealed containers.

Good luck. Serving for 25 is pretty brabve!