Before arriving in Rivendell:
Gildor: Elves routinely spend extended periods of time apart, and being immortal probably don't give too much thought to things like "Are they still alive?" during periods of relative peace like we see at the beginning of the story.
Gandalf: It seems likely that he wanted Frodo to stay in the Shire for as long as possible, being far from Dol Goldur which was the primary location of concern through the preceding decades. Knowing Bilbo was alive and well in Rivendell may have inspired Frodo to go traipsing across to Rivendell giving rise to the opportunity to lose the ring of power (noting that while Gandalf didn't know it was the one ring, he claims that it being a ring of power was obvious from the start). A ring of power on the loose doesn't sound like a recipe for continued peace, and losing it relatively close to the Necromancer (known to be Sauron for the last 77 years or so) would have been a bad idea no matter which it ring it was.
Aragorn: As Bilbo is around 128 years old at this point (almost as old as the Old Took), it's conceivable that before meeting the hobbits in Bree, Aragorn had not seen Bilbo in a long enough time that he didn't want to make a presumptuous statement about his state of health. It is noted that Bilbo had started to age again in the absence of the ring, and seemingly at an accelerated rate seeing the apparent decline in his health over the last few years of his life before taking the ship into the West. He goes from looking little older than 50 to looking over 100 in the space of roughly 20 years.
From the Last Bridge through to Rivendell I'd suggest the primary thoughts were evading the Nine and getting to Rivendell, so failing to mention Bilbo's residence in Rivendell is probably understandable.
Once they arrived in Rivendell it seems likely that the others would have had enough time to get over the novelty of Bilbo's residence there that it wouldn't feel like news by the time Frodo woke up. Alternatively, they may have been respecting Bilbo's right to experience Frodo's untainted reaction to the reunion.
Regarding the potential for spiritual buoyancy on the road, I can imagine that it could have had a significant effect in the opposite sense if the revelation was given on the road, and then on arrival in Rivendell finding that Bilbo's death had been anywhere from months to days (or even hours) earlier. It might have been enough to push him over the edge to "servant of the enemy" and inside the boundaries of Rivendell at that. I'm not convinced that such consequences were really considered by Aragorn and Glorfindel, more likely they were focussed on safely navigating the Trollshaws. (Having been there after them, I can relate ;-)