The Ainur and their physical forms

[The Saucepan Man]

Excellent post, Mr Brandybuck.

And many thanks for that quote, HI. Most interesting. I do have one question arising from it, though. If Maiar become bound to their hröar through indulgence in physical pleasures (eating, drinking, begetting etc), does that mean that Melian and Gandalf (and any other of the Istari that may have returned) remained bound to their physical form on their return to Aman? Or, once back in the Undying Lands, could they relinquish their physical form and once again assume "spiritual" form?

Actually, one more question. Am I correct in understanding that a Maia bound to his or her hröar could still assume a different form? This appears to have been the case with Sauron, who became "wedded to the form of his evil deeds" following the drowning of Numenor, but still seems to have been able to change form. It is said that he was unable thereafter to assume fair form, but this implies that he was still able to assume any non-fair form that he wished.