Definitely not. Genya remains outside the ranks of Hashira throughout the manga. This is because of a combination of factors such as his skills, experiences, and the overall direction of the story.
Well, the circumstances of Genya's death in the manga are quite complex. It involves a series of events and confrontations with powerful enemies. But I can't recall all the details at the moment.
One common theme could be adventure. Since Inosuke is a rather wild and adventurous character, fanfics might involve him and AOI going on some sort of exciting journey together, perhaps exploring a new and dangerous area.
Inosuke survives throughout the manga. The story doesn't have his death as part of the plot. His character remains active and plays a significant role until the end.