Since it’s first reveal, we haven’t learned much about Kaizoku Musou. With it’s release in 12 days, we don’t have much of a roster and many arc’s are only assumed to be included. However many users are claiming the game will have Online Co Op and Jinbei as a playable character. While this is in no way official, many online sources post accurate information like this. Additionally it appears the dummy box art also state this.
Like most rumors, take this with a gain of salt. However, do keep in mind that many previous musou titles featured online. Both Dynasty Warriors Strikeforce and Dynasty Warriors Gundam 3 featured it.