"...My doubts were awakened again to sudden fear."

[JulesWinnfield]

Is it possible that Gandalf's use of the passive voice in this sentence, coupled with Elrond's preemption of Bilbo's 111st birthday story, demonstrate a coordinated strategy by these Wise? What would that serve?

By omitting that detail, Gandalf and Elrond avoid weakening their argument for the conclusion they want the Council to draw: that the ring should be cast into the fire of Mt. Doom. If Galdor, Boromir et. al. knew how hard it was for Bilbo to give up the ring to his heir in a planned devolution, it might not be hard for them to imagine the difficulty a hypothetical bearer might have actually dropping the thing into a lava cauldron in Mordor.

Morally, this is a somewhat fraught argument. It seems to imply that Gandalf and Elrond foresaw exactly what winds up happening to Frodo in the Sammath Naur; that they were sending the bearer on an even more hopeless errand than they revealed to the council; and that they predicted that the destruction of the ring would probably require an act of providence - or at least the encouragement of the bearer by the revelation of Gandalf the Grey uncloaked.

 

[Forodan]

Well, first and foremost the author of the story had to work out a way for the Council of Elrond to come to the conclusion that he needed to continue the story. It is interesting to wonder whether he consciously worked out for himself what Elrond and Gandalf were thinking in order to do that, or if he simply juggled the narrative until it did what he wanted. Since that crucial point about the difficulty of the bearer consciously letting go of the Ring, let alone deliberately damaging it, was a blocking point, the author had to avoid it.

That said, if Tolkien did in fact try to work out what Elrond and Gandalf were thinking, it would be crediting them with far too much power of foresight to know 'exactly what winds up happening' in the end. Gandalf is very upset that he wasn't able to be present on the battlefield at Pelennor. "I could have prevented this." he says. Then why didn't he 'foresee' such an important thing as Denethor's madness if he had such powers? What they were thinking about Frodo's mission, or what Tolkien would imagine them thinking, would have been more like what Elrond said to Gimli at the departure of the fellowship when he wanted the swearing of oaths. "Look not too far ahead!" Gandalf's habit of saying "chance, if chance you call it" is relevant here. Yes, they were indeed expecting some sort of 'act of providence' as just those sorts of 'acts' had been driving the story already. Gandalf at least is trying to push Frodo (and others) to keep moving in the direction that seems to be indicated, and hoping for more such acts. This is stated pretty plainly by Elrond at the end of the chapter:

“If I understand aright all that I have heard,” he said, “I think that this task is appointed for you, Frodo; and that if you do not find a way, no one will.