He / Him
I'd say they're closer to a patron than anything. Hounds of St. Hestian could be true-believing paladins, or criminal rogues who chose to be recruited rather than locked up, or curious scholars who wish to study the Plague.Are The Hounds of St. Hestian a single class or is it a Background?
I once did a game where all the PCs were members of the Order of Inquisitors but not necessarily Clerics/Paladins themselves. It allowed for a Rogue (raised in the Temple orphanage), a Bard investigator and fighters who were non-ordained Temple guards. They worked for the Order of Inquisitors (Paladins) sent out to recover cursed/demonic artifacts when they were identified.