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!