Its not on till March 4th. They start promoting new lakorns a week or 2 before. But I think the big Ch3 preview event Perd Wic is sometime in Feb?
In the book I would say Yoi, the mom, is the main character. Then Reynu, then JJ's character and then Pilai, the 2nd daughter-in-law. The author posted somewhere that he would call those 4 characters his leads. But all the other supporting characters get a share of the pie with their own storylines. There are plenty of chapters where Reynu or the other leads disappear and have nothing to do with the stories but I skipped those lol.
And Bella and JJ's characters spend more time together in the book than with their love interest. I don't know how close they'll stick to the book.