True, but you could limit it to the enemy only, since there are no surgeons or similar in BB (yet) where a fatality would automaticaly do a type 2 death while a simple beat down a type 1. If you wish to deepen this kind of system you can always have the blunt weapons have a higher chance to do type 1 since you are more able to take enemy out without killing than with a blade.
If the whole prisoner thing is purely for the purpose of events and you won’t be able to interact with them (like in M&B selling letting go or even recruiting) then there is simply no need for a deep system. Just a random chance to get prisoners after a battle so they can start an event later on. Just a prompt of acquiring x prisoners of y type. There will be no need of detailed representation of prisoners either this way, just as much as be informative.
If the prisoner system is supposed to be deep and interactive well then first of all there should be a list of actions with the prisoners and depending of the end aims on this list should be a system made so it can satisfy every aspect.