All three cocktails are easy to mix in large batches, so you don’t have to play bartender all night. Multiply the ingredients in the Water Lily and Rosewood by the number of guests, and set each out in pitchers with a large block of ice in each to keep cool. For the Rhubarb Fizz, double the batch of rhubarb simple syrup and set out in a glass bottle alongside chilled bottles of champagne.
The beet purée for the toasts can be made a few days ahead of time and stored in an airtight container in the fridge. The watercress dip and fried artichoke hearts, however, are best made the day-of.