As the ship is still in Italy and no one has sailed on her, who's to know who gets priority boarding. Think this questions will have to sait until someone has sailed on her.
However, after reading the Carib 2002-2003 brochure on the Zuiderdam page 41, it states what Verandah Suites include and this is the same as the A & B mini-suites on the other ships. Then it states that Deluxe Verandah Suites (S), included everything that the Suites receive on the other ships. From that I would say, No, mini suites do not include priority embarkation.