Based on the WT explanation, "the rest of the anointed" have nothing more to do than any "non-anointed" Christians (as if there were such a thing). It looks like one of those unfortunate details that are left over when you misapply the parable. Kinda like when you put your car back together, after working on it, and you still have parts left over.
Just going by the parable, though, the "domestics," or "fellow slaves," would presumably have their own assignments to take care of, although, the parable does not detail that. Even the one called "faithful and discreet" had previous duties for which he showed himself, well, uh, "faithful and discreet," to such an extent that when the Master needed someone to care for the food supplies during a long trip, he was chosen for the job. None of that is detailed in the parable, but can be presumed from the little info that is given.
Of course, I think you knew all that Phizzy. Probably, the fear of questioning will take care of those 'unfortunate details.' And even if some brave soul would try questioning, he could only question the Society's gestapo, I mean, elders, who know less, and have studied less, than anyone who has dared to analyze the matter for himself. So that the leaders who have propounded this apostacy are insulated from all that. (Compare Isa 22:16 about Shebna, and the commentary below. IMO the GB are doing exactly the same.)