These Non-lethal means, as they are identifed by law, do make the gray area grayer. Most bad guys just use firearms to get what they want, which in it's own bad way, make things short and sweet. It is interesting to ponder, but it seems less likely that an attacker will be using defensive weaponry that is for the most part, non-lethal.
As far as the legal after thoughts, it is of course more defensible when one is armed and being attacked by a big bad guy with a weapon "established" as a lethal weapon. These scenarios presented, without trying to broadbrush them, seem to call for more of a retreat option response. I don't know how long the average Taser cords are, but pepper spray might have a 10 foot maximum range, depending on wind and such.