Don't confuse "Buff cannot be prevented" (like with Boba Fett, it says specifically, cannot be dispelled or prevented, so it's talking about BH resolve, and not the revive, since a revive can't be dispelled) with "Revive cannot be prevented" like NS Zombie. That might clear up the confusion.
For the boss, DN annihilate prevents revive, but zombie, whose revive cannot be prevented, still revives. But Boba Fett's BUFF is the only thing that can't be prevented (he can still get when he has Buff Immunity) but the rez itself is preventable. Similarly, with Zion, his buff cannot be prevented, but the res can.
If your question then, is about them STILL reviving, it's because the DN in question doesn't have that ability omega'd, whereas BF's "This unit cannot be revived" is baked into the execute ability. And, off the top of my head, only Zombie survives it.