[Draugohtar]

Originally Posted by TheLostPilgrim

1) Would Gandalf, Saruman, Radagast, etc--Those Maiar who were sent to Middle Earth--have any memories of their prior selves, of the Beginning?

Yes, difficult to say. I suspect the answer is yes, but perhaps with less clarity given their Valar-imposed restrictions. On returning to Aman, I would, however, suppose that their natural beings were/would be restored, including all the knowledge of their years.

2) Would Gandalf still have been Gandalf?

Yes, the continuity in personality indicated by the writing on Olorin and his time as Gandalf strongly suggest complete continuity of personality. Further Cirdan saw to his spirit, which is unchanged since coming out of the west. Cirdan acted based on that insight, suggesting he felt it a sure guarantee of 'Gandalf's' nature.

4) Will all the Ainur--including Gandalf--exist until "The End"?

Presumably yes, but some ie Sauron, not in a terribly good condition!

5) Of the Ainur in general--the Ainur are said to be the offspring of Eru's thought; Essentially, almost sort of parts of Eru. Would Eru's power or force or whatever you'd want to call it be reduced when say, the spirits of Morgoth or Sauron or Saruman are extinguished? Would those parts of Eru simply cease to exist, or is Eru unchanging and would retain the fullness of his spirit?

Indeed Eru is not bound by any restrictions or limitation of power. Further all things that come to pass are by his will.

Getting a bit religious, but, since the Ainur were the pure offspring of Eru's thought, could it be that the actions of some of his Ainur (Sauron, Saruman) were ultimately part of Eru's "Grand Plan" for Middle Earth? Ultimately, what he intended, that in doing what they did, they played a part in Eru's theme--without even consciously knowing they were doing so?

I'll let Iluvatar speak for himself:

"Mighty are the Ainur, and mightiest among them is Melkor; but that he may know, and all the Ainur, that I am Iluvatar, those things that ye have sung, I will show them forth, that ye may see what ye have done. And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined."

Eru doesn't will anything ugly or evil into the world, thus he does not intend evil to befall men or elves. BUT when evil arises Eru takes it all and 'reverts it' to the path he desires.