If you want a different design other than the standard intimate cake, then your EM will check with the bakery. Anything other than the standard cake crosses over into a "custom" cake. The bakery will take the design choice, multiply it by the guest count, and subtract the standard cake fee. The standard intimate cake should serve 30, not including the top tier which is saved for the anniversary. Some cakes will require more servings as a base count due to the design choice (i.e. squares over rounds, cake choice proportions indicated in a guest provided picture, etc.). Each case is different.
Please keep in mind these points only apply to the Grand Floridian receptions. Other resorts do the intimate cakes,but are not equiped to do the custom designs. The Grand bakery supplies almost all of the served custom cakes across property.