About Civilians: They could react in more the 2 ways.
1: Run Away in fear noticing our enemy of our presence.
2: Wave gladly at us carefull not to give our position to the enemy (if we behaved previously in the game, not shooting civilians)
3: Start yelling at us in the native toung maybe mixed with some english words More and louder yelling the worse we have played.
4: ( my favourite) Blink to us and then point out the enemy + going to the enemy and giving false testimony they have seen us somewere else =) (Only if we behaved really really well)
About other Moving civilians: Cars. Driving by. YES. Excellent idea.
Think sneaking by a house trying to hide as well as possible. Suddenly a cars drives by making you drop something in your pants. Pfeew. Only friendlys ... this time. Whats that smell??
About Proof of life: Animal sounds that gives away our position is great and could work smooth. No cpu usage unless we or our enemy is close enough to the bush, tree or rock. Then, if dices roll for it, birds fly up, frogs starts to make its sound, dogs bark, cats mjau, snakes rattle or sizzle or what ever( I guess no rattle snakes on Sumatra?) Sound stops when character moves away far enough from the trigger object. This means that if I throw a rock in a bush to draw enemies attention.. It might not work. Simply cause there might not be a bird or cat in that bush...
Not all of these things require an animation. Birds need one though. And I would love to see an angry cat or snake. Dogs could have a doghouse object. That wouldnt require an actual animation. A squeeking rat would be fun. One that we or the enemy could silence with a silenced shot =)
All animals should be possible to "silence" with a small risk of that action actually giving us away. At least if we miss the shot hitting the rock/wall/tree behind it making a richochett sound the enemy notices....
Simple stuff like flies around garbage cans is almost a must.
Running out of it....