We never seen any teaser of any upcoming team member with this game. The older Final Fantasy games uses inferior graphics so it is easier for the memory to have more party members. In a realistic next gen game, Having more features make it harder for the game to have more features because the realistic graphics takes all the effort and energy of the development team. It is also easier to give all playable characters their own shining moment if less people are playable. That is the reason why Final Fantasy VII remake have to be divided in multiple episodes.