They are. Edits in comic books could range from color adjustments to reworking dialogues or adding/removing panels to better suit the overall theme and flow.
Well, for copy editing a novel, you need to focus on language accuracy. That means correcting punctuation, fixing word usage, and ensuring the sentences are structured properly. Another important aspect is to maintain the author's voice while improving the clarity and flow of the text.
Hisoka is still alive in the manga. The storylines haven't led to his death yet. Maybe there'll be developments in the future, but for now, he's kicking.