The gaming news sites are claiming that the trailer was the full base roster (not counting possible dlc). I don't know why, the trailer itself doesn't particularly say anything about it.
It'd be super weird to have 9 characters on 3-man teams, that'll be repetitive fast, but it'll be half the price of a normal game, right ? I don't know if we should expect a much bigger cast.
If I struggled to the end of my determination, to the end of my way of life with my followers, if the result is ruin, then this ruin is inevitable. Grieve. Shed tears. But you cannot regret.