Once the potatoes are thoroughly cooked you can freeze them. You’ll still need to use them up in one to two weeks to keep the potatoes from turning gray, unless they are coated on the outside with something such as a breading.

Potato pancakes are a good option; I would also consider doing a potato croquette: taking fillings to mix in with the mashed potatoes and then rolling the outer surface in a coating of bread crumbs. Below are a couple examples.