>1) when did it suddenly become ok for the military to shoot unarmed combatants?
It has always been OK to shoot enemy combatants who are not actively communicating their intent to surrender; just because someone is not obviously armed, does not mean that he is definitely not a threat. The more important question is, "How do you know if someone is an enemy combatant?" This becomes especially difficult if the enemy does not wear proper identifying clothing or insignia. In the most unambiguous cases, the inherent right to self defense kicks in: if someone has a gun and is acting in a threatening manner, you get to shoot. Beyond that, rules of engagement will define criteria for determining if an individual or unit should be considered hostile ("hostile" has specific meaning, including, "OK to shoot at."). UBL was unambiguously an enemy combatant, so the ROE in this scenario apparently defined him as hostile.
>2) if "no one wanted detainees" why weren't the women with usama killed?
I don't think that phrase was meant to be as general as you are taking it to be. I think what was really meant was, "No one wanted to try to bring detainees out of Pakistan on the helicopters." The choice in re. UBL and his sons was to either kill them on the spot, turn them over to the Pakistanis, or fly them out on the helicopters. Turning them over to the Pakistanis has so many problems that I'm not even going to try to get into it. Trying to fly them out is risky because something could go wrong (e.g. helicopter shot down or crashed), resulting in escape, or capture by the Pakistanis. The highest priority here seems to have been closure, to get UBL out of the picture for sure, and flying him across a mountain range in a helicopter puts that objective at risk.
The same three choices (kill, turn over to Pakistan, or extract) applied to the women, but the need for closure didn't apply, so turning them over to the Pakistanis actually made the most sense.
>3) Is freezing no longer considered a form of surrender (seems especially relevant when no commands/orders were given to him?
Freezing alone has never been considered a form of surrender. Just freezing can indicate indicision, panic, or calculated caution just as easily as it can indicate a desire to surrender. Surrender requires a deliberate indication of an intent to surrender, such as putting your hands in the air or laying down on the ground. The fact that he used his wives as human shields indicated an intent to continue resisting, and he did nothing to adequately indicate that he had changed his mind and wanted instead to surrender. You can switch from fighting to surrendering at any point, right up to the moment before you are killed, but the other side has no obligation to pause at that moment to evaluate if you have changed your mind.
It has always been OK to shoot enemy combatants who are not actively communicating their intent to surrender; just because someone is not obviously armed, does not mean that he is definitely not a threat. The more important question is, "How do you know if someone is an enemy combatant?" This becomes especially difficult if the enemy does not wear proper identifying clothing or insignia. In the most unambiguous cases, the inherent right to self defense kicks in: if someone has a gun and is acting in a threatening manner, you get to shoot. Beyond that, rules of engagement will define criteria for determining if an individual or unit should be considered hostile ("hostile" has specific meaning, including, "OK to shoot at."). UBL was unambiguously an enemy combatant, so the ROE in this scenario apparently defined him as hostile.
>2) if "no one wanted detainees" why weren't the women with usama killed?
I don't think that phrase was meant to be as general as you are taking it to be. I think what was really meant was, "No one wanted to try to bring detainees out of Pakistan on the helicopters." The choice in re. UBL and his sons was to either kill them on the spot, turn them over to the Pakistanis, or fly them out on the helicopters. Turning them over to the Pakistanis has so many problems that I'm not even going to try to get into it. Trying to fly them out is risky because something could go wrong (e.g. helicopter shot down or crashed), resulting in escape, or capture by the Pakistanis. The highest priority here seems to have been closure, to get UBL out of the picture for sure, and flying him across a mountain range in a helicopter puts that objective at risk.
The same three choices (kill, turn over to Pakistan, or extract) applied to the women, but the need for closure didn't apply, so turning them over to the Pakistanis actually made the most sense.
>3) Is freezing no longer considered a form of surrender (seems especially relevant when no commands/orders were given to him?
Freezing alone has never been considered a form of surrender. Just freezing can indicate indicision, panic, or calculated caution just as easily as it can indicate a desire to surrender. Surrender requires a deliberate indication of an intent to surrender, such as putting your hands in the air or laying down on the ground. The fact that he used his wives as human shields indicated an intent to continue resisting, and he did nothing to adequately indicate that he had changed his mind and wanted instead to surrender. You can switch from fighting to surrendering at any point, right up to the moment before you are killed, but the other side has no obligation to pause at that moment to evaluate if you have changed your mind.
>4) why did "no one want detainees"?
See my answer to #2.