Denim Destroyer
Learned
In this case no, after party wiping I was able to restart the mission despite being told by the game I would have to send out a new party. However when I restarted, all four party members were shown as having zero health but I had enough supplies to heal three of them. My "undying" party member was the only one I could not heal. So essentially as of now you can have immortal party members provided you restart a mission after failure and avoid healing anybody.Could it be that anyone who "dies" is merely taken out of action or story characters can't be killed? In Battle Brothers your brothers can die, but they also have a chancce to survive being struck down at cost of getting a permanent injury.One of my squad members died but I was able to continue on as if he were some lich unable to be destroyed.
I should mention that all four members of my squad were chosen at random in the barracks and seem to have no story prevalence.