Did Kakashi have Zabuzas sword in the manga?

Kakashi is very much alive in the Boruto manga. The manga doesn't include his death. Maybe you got some misinformation or confused it with another character's fate. But for sure, Kakashi is around.

There were currently four volumes of Ronin Kenshin manga.

Sure, Kakashi is present in the Boruto manga. His role might not be as prominent as in the Naruto series, but he still has significant moments and interactions.

Maybe the storylines in Boruto didn't require his presence. The focus could be on the new generation of characters.

Kakashi is still alive in the Boruto manga. The story continues with him playing a significant role without facing death.

Yes, Kakashi does become Hokage in the manga.

Yes. The manga of Sword Art Online exists and offers fans another way to enjoy the story. It might have some differences in presentation compared to the original, but still captures the core elements.

Yes, Sword Art Online does have a manga adaptation.