But the Crusader Way to Expiation OSP should have enough content in it to overhaul the visuals of the Teutonic Order, Templar Knights, Hospitaller Knights, Crusader States, and the Islamic factions. The only thing I'd avoid in there would be the Red/White Hospitaller sets since they didn't adopt those colors until a 1259 by mandate of the pope.
You might be able to use your culture system to add some uniqueness to the Crusader States armies. For instance, the culture of Krak des Chevaliers could be set to Hospitaller, forcing its lord (The Grandmaster of the Hospitallers) to recruit Hospitaller armies from it. This would probably allow you to have Templar Order, Hospitaller Order, Kingdom of Jerusalem (in exile at Acre), Principality of Antioch, County of Tripoli armies all under one faction.