A few points:

Strictly speaking, Cirdan was introduced in LOTR. He appears in the background of one shot of the Grey Havens scene. But he's never identified, and dragging him (or Gildor, his representative!) in the Council scene would be confusing.

Gandalf already has come to be uneasy about Saruman before the confrontation and locking-up scene. In "Shadow of the Past," he tells Frodo (in the book, of course, not the film), "I might perhaps have consulted Saruman the White, but something always held me back. [..] His knowledge is deep, but his pride has grown with it, and he takes ill any meddling." I think that's actually quite consistent with Ian's performance in FotR when he tells Frodo he's going to consult with Saruman. (He sounds like his enthusiasm is a bit forced.)

Coincidentally, I'm about to write a section on telepathy for my book-in-progress on the novels. Telepathy is not just between Ring-bearers. In the scene on the way back to Rivendell when the Elves and Gandalf sit talking from mind to mind, Celeborn seems to be in on the conversation, and I've always assumed Glorfindel and maybe Erestor were, too. But those with telepathic powers seem to be able to target the person to be "spoken" to in such a way that others would not be able to "listen in." When Frodo puts on the Ring on Amon Hen, he hears both Sauron and Gandalf speaking to him mentally. At that point, Gandalf is aware of Sauron, but Sauron is not aware of Gandalf. (There are other points where Gandalf says he is looking into Saruman's or Sauron's mind, and clearly they are not aware of it.) So I can imagine that Galadriel and Gandalf could carry on a conversation in Saruman's presence--and Elrond's as well--without their being aware of it.

Finally, and I think there is a crucial reason why Gandalf seems to be deferring to all three of the others to some extent in this scene: the filmmakers seem to have decided to give Gandalf a character arc across THE HOBBIT. He starts out somewhat unsure of his own power and plans, but I predict that, with Galadriel's encouragement he goes off to investigate the mystery of the Morgul blade and the Nazguls' tombs and in doing so gains confidence in his own power. The publicity stressed that Gandalf is younger than in LotR (though sixty years younger for a 2000-year-old being isn't much). My suspicion is that we'll see him grow and mature a bit, somewhat parallel to Bilbo's growth and maturation. This seems a bit silly to me, but it's also somewhat comparable to what the screenwriters did with Aragorn in LotR, taking a perfectly confident and willing heir to the throne and giving him doubts about his own adequacy for the role of king. This notion of character arcs is a cliche of contemporary Hollywood dramaturgy. The idea that you could have a character like the book Aragorn who would not change at all across the narrative is not in the Hollywood screenplay rulebook.

I quite agree with you that Gandalf is humble, at least in his lack of ambition for a leadership role. When Galadriel suggested him as leader of the White Council, he declined. His general attitude is that he doesn't want official leadership or a settled home or anything that would give him more than an advisory role with the peoples that he is supposed to be helping. Which is not to say that in the book he isn't perfectly aware of his own abilities (and his superiority in wisdom to most or all of those around him). He's not overly humble in that regard, but he doesn't want to be praised or given official titles.

Overall, I was fairly happy with the White Council scene in the film. There are things I don't like about it, like Saruman's silly lines about Radagast eating mushrooms. (What is it with the writers that they keep acting as though pipeweed is a drug rather than simply tobacco, and putting in other drug implications?) I very much like the way the film conveys that Elrond and Galadriel are close friends of Gandalf's, something that didn't come across in LotR very much at all. I think Galadriel's respect for Gandalf is reflected in that radiant smile she gives upon seeing him after a long separation. What bothers me most, perhaps, is that way Galadriel vanishes at the end. Nothing up to this point in LotR or THE HOBBIT suggests that any of these people can just vanish and presumably turn up somewhere else. The Three Rings don't make their keepers vanish, we know that. (Galadriel is wearing Nenya during the Mirror scene, but it's the Ring that is invisible, not her.) Gandalf seems a little startled by her disappearance, but not much. I wonder if we will ever get any explanation of that completely unnecessary disappearance.