You know, I kept thinking the same thing - that the Inhuman who touched her only had the power to show people their own deaths, but I guess that wouldn't explain her first vision?
I think it would be a real slap to the fans to make it FitzSimmons after all they have been through. Hoping those two are safe.
I could see it being Mack, but since he is not an original team member, not sure if that would be considered enough bang for the buck. Logically I think Lincoln makes sense, some kind of grandiose gesture to save Daisy at the last second or something. But again, not a major character.
Pretty sure Coulson is safe, so that leaves May (mei?) that's where I would lay my money down. Her husband just died, she doesn't have a lot else going on lately except wanting to kill Ward, which would be a good way for her to go out, snuffing him once and for all. Plus she is the biggest name actor on the show and probably has plenty of other options if she wants to leave. And she's an original team member whose loss would leave a big juicy dramatic hole.
All I keep wondering is "man, the human race is about to be destroyed and no one thinks the Avengers could be of any help?!?" Even Arrow Guy? Lol...