Peter Parker is one of the main characters. He has a deep connection with Gwen. Her father is also important. He's often concerned about Gwen's safety in the dangerous world of the comic. And there are the villains like the Green Goblin who play a major role in the story.
Yes. Gwen Stacy's death is a well-known plot point in the comic world. It has had a lasting effect on the narrative and the development of other characters.
Gwen Stacy's death in the comic was a result of a cruel twist of fate. The Green Goblin was responsible for her being thrown off the bridge. Spider-Man's attempt to save her wasn't enough to prevent the fatal impact that broke her neck. This event had a huge impact on the story and the character of Spider-Man.
No, it is not appropriate. Gwen Stacy is a character from various fictional universes, and creating sexual fanfiction about her is disrespectful to the character and goes against ethical and moral standards in fan communities. Fanfiction should focus on positive, creative, and respectful interpretations of characters rather than sexualizing them.
Gwen Stacy can come back to life in certain comic iterations. The circumstances and methods of her return can vary greatly depending on the creative direction of the comic writers.
You could write action - packed fanfic. For example, create a story where Gwen Stacy teams up with other superheroes to fight a powerful villain. This would focus on her skills and bravery.
In certain comic continuities, Gwen Stacy is alive. However, her status has changed throughout different comic arcs and reboots. Sometimes she's been brought back through various means in the fictional comic world.