This does not in any way look to me like an attempt at targeted killing or assassination, by the way. So sidestepping the legal question of whether doing that is an IHL violation, I'm curious as to why you have described this attack as such.

It's targeting people who are not necessarily actively engaged in planning/doing anything. It's akin to drone strikes on random al Qaeda operatives at their houses, rather than when engaged in hostilities. Yes they are members of the enemy group, but they're not currently active combatants.