I remember the official faction rights, may override the overall server rules - if you peek into Official Factions Rights & Responsibilities section and Faction Creation Rules, it hints us the multiple ID (official) faction is allowed.
HOWEVER, I do believe that right is mainly about usage of both Generic ID and Official Faction ID by the very same faction, in my opinion serving as a promotion/restriction item within said faction - because usually Official ID comes with unreachable for generic faction pilots tech, ships, etc.
