I like your tweaks. They can ALL incorporate an unknown element. I have to say maybe I am not explaining correctly? Target distinction is more than just recognizing a threat to you. I HATE HATE HATE to use ABC's dateline or 20/20 investigation, but they DID make a point in their biased study that should be touched upon in drills. They had 2 shooters and 1 that was shooting students actually appeaared to be shooting at the bad guy who came into the room.
I guess basically what I am saying in target distinction is just that you learn to need to be eyes open to everything. Just because it is someone with a gun doesn't make them bad and it also doesn't make them good. I mean don't get me wrong either...al the tactics you are discussing are very important and should be practiced until they are instinct. They can be incorporated into different types of FOF drills though.
Perhaps target distinction can be applied to dogs as well? I will be discussing in another post though lol.
Faith Reason Fraternus