What bosses are vulnerable to stealth attacks?

[TeCoolTenno]

I heard The Sergeant can be hit with a stealth finisher (I.e. You approach him and a notification pops up on his back to play a fancy finisher move). Are all humanoid bosses like this? Can I kill Alad V, Vor, Sargas Ruk, Tyl Regor, etc with a stealth attack?

[RagingGrizzly]

I'm pretty sure all non reworked bosses are vulnerable to finishers, like Kela or Ambulas.

Edited April 6, 2016 by PUR3K1LL3R

[-Amaterasu-]

Sergeant is the only boss I know of that can be stealth killed since he uses the model of a regular crewman rather than being special in some way