The character names "Father Michael Spamloaf" and "Jerry Steinman" are listed in the film's credits but neither name is used in the film. In fact, Angst Argyle plays the interviewed priest and Robert Bullock plays Justine's whiny ex-boyfriend.
Several performers are listed in the film's credits as having multiple characters. In two cases, one of the characters is only in the prequel to this film (DMJ Part 3) that shares the entire credit list. Thus, Robbie Dee only plays "Zulu #1" and Jim Taylor plays "Daddy" in DMJ Part 4.
Troy Tanier's character is listed in the film's credits as "Slutman #3/Transvestite Voyeur". In fact, these character ID's refer to him in the prequel DMJ Part 3. His character in DMJ Part 4 is the pervert in the red jacket.