The White Council assaults Dol Guldur?

[William Cloud Hicklin]

What about Celebrian? She was still around when the Council was founded: daughter of Galadriel, wife of Elrond.

[Gordis]

I don't think Celebrian or Arwen were on the Council. Celeborn, on the other hand, I think, was there all right.

Also, as I have just read the thread, I noticed a mistake in the first post:

Possibilities not yet closed: Glorfindel, less likely Erestor, Celeborn, Galdor.

Actually rhadagastly proposed Gildor (Inglorion) not Galdor. Galdor, indeed, seems to be a mere envoy of Cirdan, but Gildor was Lord of the Noldor, a Calaquendi Elf, normally dwelling in Rivendell. I think he was on the White Council.

Also thinking of this quote

OF THE RINGS OF POWER AND THE THIRD AGE
But at length the Shadow returned and its power increased; and in that time was first made the Council of the Wise that is called the White Council, and therein were Elrond and Galadriel and Círdan, and other lords of the Eldar, and with them were Mithrandir and Curunír.

I would say that Glorfindel certainly was there, likely Erestor, and maybe a couple more Elf Lords from Rivendell. Glorfindel says:

There are few even in Rivendell that can ride openly against the Nine; but such as there were, Elrond sent out north, west, and south.

I suppose you have to be a Calaquendi Elf to ride against a nazgul. Glorfindel alone took the most probable road, but two more Elf lords were sent north and South. Here are 2 more guys for the White Council.

Actually I think the Council counted numerous members, most of whom followed Saruman over Gandalf. The ones listed in the first post (Galadriel, Elrond, Círdan, Glorfindel) would likely vote for Gandalf, but note: the majority was always for Saruman. I imagine Celeborn usually voting against his spouse. Likely some members were more or less nominal, and didn't attend every meeting. I think Radagast was a member, but not a very active one, preferring his home at Rhosgobel to the talk of politics. Cirdan was likely a rare guest as well, maybe sending a representative instead.

And no Thranduil - nobody called him to the White Council of 2941, he was at home at this time. And Mirkwood had tense relations with "the Wise", especially Noldorin Elves since Oropher's times. Moreover, Thranduil got no Ring to defend his land and must have felt frustrated.

[Legate of Amon Lanc]

Originally Posted by Gordis

Also, as I have just read the thread, I noticed a mistake in the first post:
Actually rhadagastly proposed Gildor (Inglorion) not Galdor. Galdor, indeed, seems to be a mere envoy of Cirdan, but Gildor was Lord of the Noldor, a Calaquendi Elf, normally dwelling in Rivendell. I think he was on the White Council.

Oh, I see I must have misread it back then. Anyway, even concerning Gildor... he was a Noldo, that's true, but that does not automatically mean he was on the Council. He does not seem to me to be much of the "Council type". Remember it was an "organisation" of rather "political" nature, so to say. Gildor, at least to me, did not seem to be the type of a person who'd meddle into institutions such as this. To go and watch the stars, to make a pilgrimage to the White Towers and look at the Sea, to sing to Elbereth, but in the Council, he would say "yes" and "no" on everything... (although that actually would be an argument for his presence. He would be one of those hesitating who'd eventually help Saruman by not saying their opinion aloud, or not holding to it).

Originally Posted by Gordis

I suppose you have to be a Calaquendi Elf to ride against a nazgul. Glorfindel alone took the most probable road, but two more Elf lords were sent north and South. Here are 2 more guys for the White Council.

True. But once again, being a powerful Calaquendi does not equate being in the Council. It would need to be judged depending on who these two (or more) were as individuals. Surely not every powerful warrior needed to be in the White Council (quite the opposite). And personally I don't think the Council had more than, let's say, ten members (cca). It was no Roman Senate.

Originally Posted by Nazgûl-king

I always thought all five of the Istari were on the White Council.

Well, even if we relativised the quote suggesting that only Saruman and Gandalf were there, at least with Alatar and Pallando there will be the problem that they might have disappeared to the East before the Council was ever formed in the first place; and that's very likely. Had the Council existed by the time they left to the East, it will be probably the Council that would have sent them. But as far as we know, it was Saruman's ("wilful") act. It's also possible some "proto-council" had their hands in sending them to the East, but from how I read it, it seems to me indeed more like a "private" action. In any case, I believe the two were not in any Council, simply because it did not yet exist when they were still around (although I'm sure they would have been in it if they had the chance).