"Credit only" technical question

Hello. This is sort of a followup to my previous post, about adding cast members (right now to Rabbit Academy: The Series.)

In the end credits of every episode there's a list of cast members. The names are not associated with characters, just listed under a "voice cast" heading. This list does not change between episodes. Though the information isn't in the credits themselves, resources like fernsehserien. de tell which actors voice which characters. The thing is, even though the entire cast is listed each time, not every character appears in every episode. I found this attribute from the documentation that seems to solve this problem:

credit only: Someone is credited, but did no work - this is most common for a TV series, where a regular cast member does not appear in a particular episode. This is distinct from (scenes deleted), in that there were no actual scenes filmed. This includes news/talk/entertainment series with a person’s name in the title (e.g., The Tonight Show Starring Johnny Carson, Tucker Carlson Tonight), when a guest host appears.

My question is, is there a streamlined way to set this attribute per episode? When adding a cast member, it seems I can only add an overall attribute. Must I go into every individual episode and add the cast members there? Would it be permissible to add the whole cast to every episode and then, when I have the time to scrub through the episodes and determine who talks and who doesn't in each, go back and add the (credit only) attribute to characters/actors who don't speak? Or would that be considered adding incorrect information and disallowed? Does the character names being listed or not in the credits make a difference? For instance, if you know Tom Raczko plays Calloway from an external resource, you could tell which episodes he speaks in, but from the end credits alone you can't tell whether he speaks or not in a given episode, so I could see that factoring in (or maybe it doesn't matter and I'm wrong.)

Thank you,Nev E.