can I make the cheese fondue ahead and then reheat it?

I'd say no...there are too many variables and you'd probably end up with grainy cheese.
If you're worried about service just preprep the cheese and store in plastic bags, along with other things that are chopped. and even a plastic of flour and other dry stuff pre-measured. Make it a "kit" format..and through it together at the last moment.

nooooo. i adore cheese fondue in the winter but boy it does not reheat well. the mass os hardened melted cheese does not like to become smooth and silky again.