Yes, you can use any other type of vendor that is not on the buildings list except for the catering, bar catering and rental companies. The only requirement is they must be a professional company that has a business license and business insurance.
Regarding a florist please know that you must hire a professional florist to set up and break down all floral items that are brought into the space. All florists must show up at the end of the event to break down and remove all floral and décor rentals from the property. If this is not done, and the on-site coordinator or cleaning company removes any floral or décor, $500 will be deducted from your damage deposit.