I'm seeing this around twitter that the cast was datamined and I'm even seeing news from Shonen Jump leaks saying that Law is being added.
https://twitter.com/EMUNOPLA/status/1098800065269956608
https://twitter.com/ScotchInformer/status/1098798249710895104
So them confirmed Law and even mentioning Biscuit add value to the data mine.
Force me to join Jump Force if true.