Can these Oktoberfest dishes be reheated without ruining them?
The potato salad, and the peppers and onions, are standard steam-tray fare. If you can, make them somewhat ahead of time and keep warm, covered, in a low oven. The brats can be treated likewise, though you won’t maintain the same crackle to the casing; your can re-crisp in a fan assist oven for 5-10 minutes at 200C.
Don’t mess with the preparation instructions for the cheese. It’s the least stable of the four.