first, that the story of Mithrellas is more than rumor (something the Prince
Imrahil himself apparently did not know for sure) and second, that the Tooks
did not marry any elves (I did not see Legolas greet any of the hobbits like he
greeted the Prince Imrahil) but are simply, as you suggest, Elf-friends, and,
like Elanor Gamgee, the blessed children of Elf-friends.
Why is the union with Mithrellas not counted among the three great unions of
legend? Because Mithrellas, an ordinary wood-elf was not as highborn as
Luthien, Idril, or Arwen, and her human husband was not as highborn as Beren,
Tuor, or Aragorn.
Legolas does not give the Prince Imrahil his own name or Gimli's, perhaps
because his message from Aragorn is urgent, and he does not want to waste time
with all the niceties that would surround a formal introduction.
Why aren't Gimli and Legolas attending the Council of the Captains? The
sons of Elrond do so, and they lead no troops. Did Legolas and Gimli beg
leave to see the hobbits instead? That would be my guess. They
trusted Gandalf and Aragorn to make the right decision, and knew that if they
wanted to visit the hobbits they had better do so instead of joining the
Council.
The people of Gondor seem remarkably willing to follow Aragorn's lead. Of
course he seems to have fulfilled various prophecies, and Faramir apparently
saw him on the "other side," but still, I cannot imagine such quick acceptance
of Aragorn's claim in the Primary World. Furthermore, the Captains are
about to lead a force of 7000 on a suicide mission against the might of
Mordor. The Captains know about the Ring, but surely the troops do
not. So they must take it on trust that the Captains know what they are
doing. Considering the fact that a few days ago none of the Captains,
including the Prince Imrahil, had any authority in Minas Tirith, that is a lot
of trust on short notice. Perhaps our heroes are not the only people in
Middle-earth capable of quickly assessing the worth of strangers, or of
recognizing noble or elvish blood. Perhaps the general populace of Minas
Tirith has a similar ability. On the other hand, with all the Captains
united, where else are they going to turn?
As I have noted before, I do not believe Aragorn is merely being cautious or
diplomatic. He genuinely does not want the crown unless it is thrust upon
him, and he is delaying that moment as long as
possible.
“I dislike Allegory - the conscious and intentional allegory - yet any attempt to explain the purport of myth or fairytale must use allegorical language. (And, of course, the more 'life' a story has the more readily will it be susceptible of allegorical interpretations: while the better a deliberate allegory is made the more nearly will it be acceptable just as a story.)” (From Tolkien Letter # 131.)