Hi,
Of course, you can't have characteristics for all the dropdowns on that product page. That would be too much to handle for the database as you saw previously.
So here is a solution which will work : Keep the last one "Add a Flavor Shot" as an option.
For all the other dropdowns, instead of using an option, you could use instead a custom field of the table "item". You can create them via the menu Display>Custom fields with the Business edition. You'll be able to have the same display, but with the custom fields, you'll be able to have a "please select" choice and set the field to be required and the system won't let the customer proceed unless he selects something else in the dropdown.
The custom fields are even less database intensive than the options, so it should be even faster for the processing of the page.