There's no evidence to suggest that Katherine Barrell reads fanfiction. Fanfiction is a bit of a niche area and not all actors engage with it. It could be that she's never even been exposed to it or she might be into it privately, but without any statement from her or her team, we can't really know.
Glenn meets his demise in the comics during a particularly intense and chaotic event. The circumstances surrounding it are quite harrowing and have a significant impact on the story's direction.
Negan's death in the comics occurs at a specific point, but I can't recall exactly when off the top of my head. You might need to do a detailed search or refer to dedicated comic forums for the precise moment.
Iron Man meets his end in a particular comic arc where the circumstances are both intense and unexpected. It's a turning point that shakes up the entire comic landscape.
There's no clear indication that Katherine Barrell has a particular interest in science fiction books. Her work might not directly relate to this genre, so it's hard to tell if she enjoys reading such books or not.
She might want to manipulate Elena. Katherine is known for her devious ways, and by sharing her story, she could be trying to gain Elena's trust or sympathy for her own purposes.