I agree with Andrew. In your business plan, when you decide on your drink menu, you may have say 10 to 12 items (ie. mocha, latte, cap, americano, etc.). In addition to that menu, you could have a seasonal menu of 3 or 4 items that come and go with each season. Springtime menu items could contain strawberry ice cream, (strawberry mocha frap, strawberry latte frap, strawberry espresso milkshake). Summertime could have one or two summer drinks and a vanilla espresso milkshake. Fall could have three or four fall flavors and so on.
This way you do not have a crowded menu, your operations will be smoother, and you can offer one or two flavors at a time to keep fresh ice cream. During cold months, when ice cream sales are down, you can keep ice cream off the menu. If you only offer one flavor of ice cream in a specific drink, you will not need a very big freezer either. Speaking of freezers, can you fit an ice cream freezer close enough to the barista station, to make it easy and quick to access?