I've been unwell for a few days so haven't been keeping up with this thread. I've had a quick read through, but apologise if this point has already been covered.
Re shooting aircrew in their parachutes from the ground. There is plenty of evidence that this practice was at the very least not unknown in WW2. A famous example of course is Flt Lt James Nicholson, who won the only Victoria Cross for the Battle of Britain. After bailing out from his burning Hurricane over Hampshire, Nicholson was fired on as he landed by a Home Guard who mistook him for a German, and sustained shotgun wounds to add to his burns. Not sure what the policy was, although I'm sure shooting on your own side was not permitted!
More seriously I have read a comment from a WW2 fighter pilot (I wish I could remember the reference) that he couldn't fault German pilots who fired on British aircrew as they descended by parachute over the UK, as they could be back up flying within hours and thus could be considered fair game. Whether this opinion was widely held I dont know, but at least it demonstrates that the practice is not some new barbaric product of the current hostilities.