Can these Oktoberfest dishes be reheated without ruining them? I am hosting an Oktoberfest party tonight and would like to do much of the cooking this morning and just re-heat things before the party for time management purposes. Fortunately, I have a good friend that is a retired executive chef bringing schnitzel, but I am responsible for everything else. Here is what I'd like to make ahead:

German potato salad
Beer cheese (for pretzel dipping)
Beer brats (thinking of grilling early and then heating in the oven)
Saute peppers and onions as a condiment for brats

Can all of this be successfully reheated without making it awful? If so, what temperature? I have two ovens and can do two different temperatures if necessary.
Thanks in advance!
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.