Misc. Questions

[Lalaith]

I believe, although I don't have the texts to hand, that the three rings were made, and presumably used and worn, before the Alliance. The making of the Three seemed to coincide with the unmasking of Sauron by Celebrimbor at Eregion.
As for this:

On foot even Glorfindel and Aragorn together could not with stand all the Nine at once

I think we cannot read too many "power comparisons" in to this comment, between the various elves in LotR - it must be taken in the context of what the reader does and does not know at this point in the narrative.
At the point in the story that Gandalf says this, we have not yet met Galadriel and know very little of Cirdan. Elrond is clearly not going to leave Rivendell and so there is no question of him confronting the Nine on the road.