If I were you, I would not go out and buy a coffee maker since you do not drink coffee.
I would not serve instant coffee in my house, but I am set up to brew coffee, you are not and should not be expected to.
I am addicted to coffee and will consume it any way I find it, instant if that all there is. It is obvious you are going out of your way to please your American company and they will see that. I am guessing that the Americans have noticed that coffee is not the beverage of choice and they may try to obtain their own source even before they arrive for breakfast. Maybe even in their hotel room?
When I am a guest in someones house in a foreign country, I expect to gratefully eat what they serve me.