That's roughly right, but that doesn't make him in any meaningful way "good". Of course I also don't think anyone who decided to drop the bombs on Japan was a "good guy". But maybe that's why I'm not a pure utilitarian.

Veidt asked the precognitive being if his plans for utopia would come to be, and if it was all worth it in the end. Osterman cryptically responded by saying "Nothing ever ends", and teleported away leaving Veidt once again in doubt as to whether or not his plan was successful.

From what I understood, he spent the whole story acting super-sure about what would happen if he did nothing, and how he alone could fix it. But in the end of the comic, this showed he had doubts. Veidt didnt have precognition, just very good prediction. But also an over-inflated ego. He killed a lot of people for a "maybe".

Rorschach being good is debatable, he's a Batman like vigilante who hasn't the 'no killing' rule, which is dubious.

But the reason he chose death was (in my humble opinion) that he realized Veidt had found the solution, that would bring peace and create a world he would be useless in.

This point is made by the ultra nationalist frontiersman publication he sent his diary to. They complain that they have nothing to write about as the world was united in boring peace, this is when the burger munching intern gets the assignment to pull something out of the loonie pile.