User Registration with selection of Roles

I'm using FF Pro & User Registration AddOn to develop an online Entry site for car shows. The site will allow site Registration for Administrator (me), Concours Chair (an event organizer), Entrant (person entering a car), and Judge. Since the same person may play more than one role, there will be 4 checkboxes.

What I deed to know is how to make the necessary restrictions. E.g., only an Administrator can modify the code, only a Concours Chair can create a new concours event, in order to sign up as a Judge he/she must be Certified by the club.

My thinking is to let the prospective site user to check the desired boxes and filling the rest of the data. If Administrator, Concours Chair, or Administrator is checked, through up a read only Paragraph field saying "we'll register you as an Entrant for now and change your role and notify you if approved."  That's easy. But how do I change the role selection to "Entrant" before or during the Submit process?

Or, is there a better way of handling this?

Ed