Yeah I'm starting to think Kelsey Grammar is not returning either. Hank is slain in the future anyway, as is Kurt, but of course that doesn't mean they wouldn't still could appear in cameo roles as unlikely as that is as well.
Why do people keep bringing up who is shown to be dead or alive in the original DOFP story's future? It means absolutely nothing
in terms of how the story is adapted to screen.
Here is the basic framework of this story: an important political figure is assassinated, which creates a dystopian, anti-mutant future. A survivor from that future travels to the past in order to avert it. That's it.
Those are the broad strokes of the story. Everything else is up in the air from an adaptation standpoint. But if you lost the bits I mentioned above, it would no longer be DOFP in any recognizable way, so they at least have to keep that. Who is alive and who is dead in the future, according to the original story? Totally irrelevant.
It honestly makes me sad when comic book fans seem to be so unimaginative about these things.