no, not everyone working in the agency has to be qualified and iscritto - last time I checked, for the company (a societa' di capitali, there are different rules for different types of company) to be iscritto (the entire company), only the rappresentante legale has to be iscritto as an individual. I am talking about companies registered in Italy of course.
I think you'd find it extremely difficult to find a single estate agency in Italy where every employee is iscritto individually.
Charles has already answered this question actually: see here
http://www.italymag.co.uk/forums/sho...6&postcount=30