In the Dr Stone web novel, the main character is Senku. His intelligence and determination are what drive the story forward. He has an encyclopedic knowledge of science which he uses to his advantage. Taiju is his friend, a big - hearted and physically strong guy. He provides the muscle power when needed. Yuzuriha is also important. She is not only Taiju's love but also has her own skills and ideas that contribute to the group. There are other characters like Chrome, a self - taught scientist, who later joins Senku's group and helps in their scientific pursuits. Each character brings something unique to the story and their interactions shape the development of the plot.
Well, Senku is the protagonist without a doubt. He's the brains behind all the scientific endeavors in the story. Taiju is his best friend, and he's always there to support Senku, whether it's by providing brute force for physical tasks or just being a loyal friend. Yuzuriha is also an important part of the main group. She has a gentle nature but is also very capable. There are other characters too, like Chrome who becomes an important ally later on, but Senku, Taiju and Yuzuriha are the main characters that set the story in motion.
At the moment, there's no definite information about more Dr Stone manga. It could happen if there's enough demand and the creative team is up for it. We'll just have to wait and see.
It's hard to say for sure. The decision often depends on various factors like the popularity and sales of the original series, as well as the author's plans and the publisher's strategy.