Personally I tend not to advocate two stamina trinkets at the same time. I prefer one stam trinket and one avoidance one. As such, I'd say Skel key/Corpse tongue.
Honestly though I'm lousy at math. I expect Stam Czar will be behind me in a second to prove that the stam+armor buff on TBH offers a higher effective health than the stam+dmg absorb on Key.
Either way, Corpse tongue+ one of the other two is the better way to go I think.