Inherent evil?

[Mhoram]

Melkor's motives were thus primarily egoistic.

So would you say that his intentions when getting out of tune weren't to create ill, but to create perfection as he envisioned it? Much like Saruman's plans for ruling with perfect order? But after everything got screwed up and he realized the other ainur weren't going along with his vision, he would be forever after in conflict with them, striving to either finally succeed in his plan or atleast get the other ainur back for messing up his plan?

They would be Morgoth's greatest Sins, abuses of his highest privilege, and would be creatures begotten of Sin, and naturally bad.

even Orcs would become part of the World, which is God's and ultimately good.)

Do these statements not conflict?

But Eru's words clarify: "...And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me..."

Eru proving just how hot-to-trot he is by letting Melkor try to mess things up but in the end it all working out just as Eru had intended?