I don't know very much about the names taken by those in service to the church, but if the character is known to all as Father Calebrese, that's his name. It's not necessary to know that his first name is Bill and his family (mom,dad, sibs cousins, etc.) calls him Junior, because he only appears briefly and the POV character will never get to know him that well.
Just as I remember my fifth grade teacher as Mr. Fiorito, our small-town preacher as Mr. Landsrs, the school bus driver as Shorty and Grandma's brother as Uncle Steven, that's all your main character needs to know.
I like to play with character names. Using smart names can reveal much about the character. Is he a redneck? A Frenchman? Is she a stripper? Extreme examples, I know, but it does help to define the character without extensive descriptions. And they do need names. It might feel like you can get away with 'the cop' or 'the shortstop,' or 'the conductor,' but as CJ says, you don't want to have to describe them time after time. That's tedious, and you don't want to bore your readers, right?
I'm currently working on a seven-part serial in which the names have foreign language meaning that describes the characters. For example, the murder victim was Luz Apagada, which is an approximation in Spanish for 'lights out.' Next month's issue features a gluttonous character whose name in Malaysian means 'fat man.' while his female assistant bears the name Chichu, which is my phonetic spelling of the Mandarin word for 'spider.'
Be that as it may, I would say to use logic in naming characters. Simply consider how well your main character knows each one, and that will clue you in to how deeply you need to go into naming them. Enjoy the journey! JP
P.S. If your POV character never meets them, but only sees them from afar, they won't need names. Your POV character can think of them as 'the cop' who directs traffic, 'the shortstop' at the game, or 'the conductor' on the train.