Montero gets exposed against pacey strikers. To make things worse, Legro, Iluliano, Tudor, Ferrara arent quickest defenders around. Personally, I would keep Legro to give him one last chance, and Ferrara as he can provide veteran presence both on and off the pitch.
Nonetheless, I think their future will depend on the formation Capello intends to use: If Don Fabio believes in 3 men backline then I can see him having 5 CBs in the team. Preferrably, I would buy at least 2 of them from the transfer market, and try to fill in other 3 spots within the team. If that is the case maybe Iluliano and Montero can make the squad, as especially in latter's case he played majority of his career as sweeper.
However, at the end of day, what really matter is who we brings in, because they are the guys who will ultimately start IMO.