And yes, I disagree with the 2006 Supreme Court ruling.
And if you really cared, the Geneva Convention, and your interpretation, also would NOT have allowed the assassination of bin Laden and his wives. I didn't hear you raising an issue then.
Rosen, cited in your points, says, "assuming the family members are not combatants themselves..." They ARE combatants both by commission and omission.
Certainly, letting ISIS have its wish to become a country (the only non Geneva signatory) would also give it its wish to die for Allah with a minimum of muss and fuss.
I would expect to see a lot of bail-outs from ISIS very shortly after that happens.