Certainly Natalie’s target should be Angelique, but Natalie doesn’t know about the “anyone who loves you will die” part of the curse. All she knows is that Barnabas is a vampire, and that Barnabas, as a vampire, pursued Josette. From Natalie's point of view, Barnabas chose to pursue Josette, when he could have left her alone. Natalie doesn’t know how hard Angelique worked to make that pursuit happen.
You make great points, and I would be 100% on board for most other characters. But we're talking about Natalie, who is knowledgeable about witchcraft and expert at the Tarot, so she is well acquainted with the principle of cause and effect. While it's true she doesn't know that the curse affects everyone that loves Barnabas, she also doesn't know about B&A's affair in Martinique, and at this point she
does know that vampire Barnabas victimized Josette because of a curse placed by Angelique, a witch who hid her powers for years as she played the role of a DuPres servant, living under the same roof with Natalie and pretending to be loyal to Josette, and who [spoiler]mocked Natalie when Bathia was brought in to lift the curse...[/spoiler] I think Natalie would be more apt to feel pity for Barnabas and want to throttle the deceitful Angelique for betraying all of them and setting the tragedy in motion, but that's me.
As to other changes, Ben deserved better than to be turned into a cold-blooded murderer, and Natalie deserved better than to be buried in an unmarked grave. Of course... [spoiler]if one is patient enough, their histories will be rewritten yet again. <sigh>[/spoiler]
As for the “I saw him die” stuff...all I can figure is that Natalie assumed that the Barnabas’s curse was a Sleeping Beauty or Snow White sort of curse, and that when Joshua told Natalie that [spoiler]Bathia Mapes had failed[/spoiler]he said it in such a way as to suggest that Barnabas had slipped from sleep into death – so that the original death might as well have been death. (And never mind the fact that I don’t think Natalie did see Barnabas die his first death.) This isn’t a very good rationalization, but it’s the best I can do.
LOL And you're right-- not matter when Natalie thinks he died, she still didn't see it.