The Maiar

[TheLostPilgrim]

I have a question:

Maiar are Ainur, correct? I've never understood the distinction between the Valar and the Maiar--I thought they were all the same sort of "being." What sets the Valar from the Maiar?

Also, were the Maiar present at the Ainulindalë, were all the Ainur created at the same time? Did the Maiar help shape Arda? Or were the Maiar created later?

I just wonder at it, because it's interesting to think of the idea that Sauron, Saruman and Gandalf, would've in their own small way helped literally shape Middle Earth.

This leads me to a secondary set of questions:

1) Would Gandalf, Saruman, Radagast, etc--Those Maiar who were sent to Middle Earth--have any memories of their prior selves, of the Beginning? Of themselves before they were "Wizards"? Would they still retain the memory or knowledge of their true selves, the extent of what they truly were, and where they came from? Would Saruman, by the time of his Fall, have forgotten that he was a Maiar, who shaped the history of Middle Earth in a small way, that he was ultimately a servant or creation of Eru?

2) Would Gandalf still have been Gandalf? What I mean is, once he returned to the West, would he still have retained his personality, emotions and his memories of Middle Earth, of Frodo, etc? Would his spirit, his nature, still be recognizable as "Gandalf" in his natural form as Olorin? I don't mean who Gandalf was physically; I mean who he was in terms of his personality, his traits, etc?

3) Have we ever gotten any indication of what the Istari, or Maiar in general, look like in their "true" forms? I've read the Istari were simply "clothed" in the bodies of old men...I wonder what their true forms looked like.

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

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?

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?