Yes, but they rarely use the true names of the characters that would be recognizable in the casting calls.
Yeah, but they HAVE used the true names of the characters when it’s no longer a secret that they or their stories will be touched upon in the series. Examples of this are the casting calls of Captain Hook and Prince Philip (cast weeks after Princess Aurora was).
As far as Rufio goes, all I can say is if it’s a placeholder name for someone else, they should have chosen a different name, because now there are quite a few fans excited about actual Rufio being on the show, and I imagine they’ll be quite disappointed if it’s not the case.