Got a suggestion for you for this Inquisition faction.
Make them Spaniards that disagree with the "impure" lifestyle of the Corsairs and the Outcasts and have those two factions be their primary enemy rather than all smugglers, pirates, etc.
Their mission could be to restore the sons of Spain to a lifestyle of honor and purity, instead of the cesspool of crime and sin they have become.
The Vigilante ID would fit best.
Maybe combine that with a Bounty Hunter IFF?
I see that my first idea was wrong...
But few Yours sugestions it might work - now I have to choose between sugestion of Soldier's Requiem and Hideki.
so - or something like Border police, who work only in independed and border space
or - Inquisition who fights with brothers and sisters who choose a path of pirate and sin (Outcasts and Corsairs)