The Hashiras would likely show concern. Some, like Shinobu, would immediately start looking into possible medical solutions. Giyuu might be more reserved in his worry but would still keep a close eye on Tanjiro. The other demon slayers would also be affected. They look up to Tanjiro, so his sickness would lower the morale of the group. They would try to support each other while waiting for Tanjiro to recover.
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.
It's hard to give an exact number. Different story arcs and battles led to the deaths of multiple hashira. Some died heroically, while others met their fate in unexpected ways. The count changes as the manga progresses.
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.
The first season of Celebrating Years was a high-profile TV series. The audience said that they could watch it all in one go. Some people expressed that they were very satisfied after watching four episodes in one go. There was also a collection that included the first season of the celebration, so the audience could watch it all in one go. Thus, Qing Yunian could finish the first season in one go.
The first season of 'Celebrating Years' could be watched in one go. Although there was no specific mention of the length of the one-time viewing time, there were related videos that mentioned " watching in one breath " and " 70-minute exclusive version ", which meant that the first season could be watched in a relatively short time.