Well, there isn't much of invidual every day morality in LOTR basically. It's more of a morality for kings tale.
who is the most moral character? Gandalf. And he is a mouthpiece from the Valar to men.
Who are the most moral people? The elves. They're closest to the Valar and are always good, to the point you can debate whether they have free will or not.
What's the job of a moral ruler? To fight the beasts of Morgoth and men not from the north west, all the people that never got told morality from the Elves in ancient times.
what's the ultimate sin? to challenge God and the Valar, of course. God will sink your continent to the sea and reshape the planet if you dare.