I don't know exactly. It could depend on the specific manga universe or storyline. Maybe you can search through popular manga forums or fan communities for the answer.
Inosuke doesn't become a Hashira in the manga. The story progresses with him having other significant experiences and achievements instead of achieving that specific position.
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.
They have a complex and somewhat ambiguous relationship. It's not straightforward love but a deep connection based on mutual understanding and shared experiences.