RE: potato/fries/steaks questions
finished mashed potatoes don't hold very well, they tend to become dry and crumbly after about an hour on the steam table. where i worked years ago, we went through a >lot< of potatoes so we always had boiled unpeeled potatoes in our cooler. when someone ordered mashed, the pre-cooked potatoes would be reheated in hot water for a few minutes, then peeled and mashed fresh with butter and milk, roasted garlic etc.. usually about 2 orders worth at a time.
i think most of the chains use frozen fries that are coated with a light batter that has the spices in it, this is so that they will cook up crispy without using hydrogenated shortening. some places use old bay on their fries, personally i like a good garlic salt. :)
we cooked our steaks on a flat grill along with everything else, so it was just a matter of keeping the griddle at the proper temperature and always use an accurate timer and grill thermometer. all of our meat came from the supplier in very consistent portions (thickness), so it wasn't too hard to come up with accurate times for rare, medium, etc.