Hi, Doug. According to the WTS definition of the FDS, the thing to remember is that they are made up of all the "anointed" who are on earth at any one moment in time. That last phrase becomes important when you get close to definitions. Remember Paul? Yep. Well he was "anointed" so he was part of the FDS. But, and this becomes a big but - he is not of the FDS now!! He's not on earth anymore see? The same goes for all those of the "anointed" who have passed on. They were, as long as they were alive, part of the FDS, but they no longer fulfill that esteemed role. Presumably they are all contemplating their collective navels right now up there in heaven, and according to the Revelation Climax, though they are deceased, and the Bible forbids communication with the dead, the present day FDS get many "truths" from their mates who have passed on.
The relationship between the "anointed" and the GB is a checkered one. Technically, these "anointed" ones get together in quorum and "elect" the various members of the GB, to lead them. In practice this is an empty sham. The GB is a self perpetuating organism which arbitrarily decides to choose any whom they want among their ranks. Naturally they only pick the die hard company men.
The original view was that "Jehovah" communicated his truths to Christ who then through "holy spirit" somehow conveyed these to the "anointed" When that drunken lout Rutherford came along, he decided that the end was so near, that the "holy spirit" had ceased to function. Now it was "angelic beings" who did the conveyance. To Rutherford only. Evidently the "anointed" were left out of the loop. With his passing this humbug was discarded and the original view renewed. With no clarification, or any acknowledgment that any change had occurred.
The finer points and the mechanics of how all the plumbing works has never been detailed, and the R&F are simply too somnolent to make inquiries. The polite fiction simply carries on. Unchallenged.
Cheers