The dynamic dropdowns functions are going to be removed in the next version of DataBridge in favor of using AJAX and framework builder to achieve the same result. This is something I will do a tutorial on in the future (possibly a video tutorial). If you need dynamic dropdowns with mySQLi immediately, this is something I can show you how to do in a premier support ticket.
I did update your dropdowns on the page to use MySQLi so they are at least populated. Several of them still had mysql code.