3) True, but you lose a lot of potential points to increase your soldiers stats, specially accuracy and reflexes. I did this, but 15 - 20 missions later, i got a terror mission and realised how crappy my soldiers aim and reflexes were. They couldnt shoot anything.
4) There is a drop of blood icon next to the soldiers picture, when he is bleeding, when it disappears he has stopped, he also leaves a blood splatter on whatever tile he is on.