Does Eru care?

[TheLostPilgrim]

In The Silmarillion it is said that the entire history of the world is the product of the music of the Ainur, and they helped to shape the world and it's history through the Music they made, whose utmost source was the Theme given to them by Eru; The Ainur are the offspring of Eru's thought; Each Ainur being part or understanding only of that part of the mind of Eru from whence he or she came...So, logically, would it not be that the vanity and pride of Melkor came from a part of Eru's mind? What Melkor understood--vanity, a desire for power, a creative urge at best--would that not have come from some part of Eru's thought?

And also logically following, would not all the horrors (and beauty) of Middle Earth's history be, indirectly, the product of Eru's vision, of His music?

Also, from what I remember, Eru did not seem to intervene much in the affairs or woes of Arda or his Children, but instead, the Valar and Maia seemed to be more responsible for Arda...Eru seems to have sort of taken a distance to the world he created, whereas the Valar (of both kinds) seem to be more involved and hold more a care to it.

But even the Valar--Did they not cease intervening and helping directly in the affairs of the Children of Illuvatar after Aman was attacked? In their last action, they sent the Istari--but only to act as messengers or as guiding figures to the Children; Not to use their might to contend with Sauron and defeat him and set the world to right, and also they placed strict limits upon the Istari's use or display of their power.

It's obvious some of the Maia and Valar did care; Gandalf being perhaps the best, most direct example...But what of the Valar as a whole? Or Eru? What regard do they hold for the fate of Arda and it's peoples?

A last off topic question but: Who would be more responsible for Arda's creation? Eru or the Ainur? Eru laid the Foundation--the Theme--for them to play and by which create and shape the World, but it was their Music--each intricate, individual part which they themselves crafted based on Eru's theme--which directly shaped the world.