TBH you only need explosives, be it grenade or mine or remote detonated explosive, no need for stuns gun cause they get stunned for 2-3 seconds when caught in an explosion regardless and during this time you can drop in another explosive...by doing this you can practically defeat the boss under 10 seconds without him or her barely even moving. And I did this all when I was playing on full stealth on hard during my very first playthrough.