I have seen purple fountain grass planted in several places near the beach. And it is thriving.

IMO
there's two types of "salt tolerance"
one is salty soil
the other, salt wind and drift

muhly grass, (and other ornamental grasses) around here, can handle both, providing soil is moist enough

A definitive YES for salt tolerance on all four plants you mentioned. These specimens are thriving in my garden.

Kathy
I'm in your area and I just planted 5 muhlys in a new bed on the east side of my property. What do you do to yours so they thrive?

Pcola --
Muhly grass is a carefree plant requiring no extraordinary care, just watering when dry. In fact the clump has grown so large that I have been able to share. But that was tough -- I needed a machete to cut through the roots!!! Good luck to you!