Six Days in Fallujah

Can everyone on your fireteam die like even people who actually survived the battle or will they just be invincible like main characters from call of duty or will you guys use randomly generated marines/soldiers

Most of the time, friendly AI fireteam members can become incapacitated at any time, depending on your actions as fireteam leader. There are some exceptions to this with characters during the narrative campaign.

There are also cases in which you cannot progress to the next mission unless your AI teammates make it through the previous one.