As Bowles said, there's no point in thinking of these guys as free safeties/strong safeties. They are both interchangeable safeties and will play roles in the box and coverage. They may excel at one or the other, but will do both.
I am interested to see if Bowles/Macc are serious about keeping Pryor. I can't imagine we could get much for him anyway. Unless he becomes a problem, might as well let him play out the year on the cheap. He can start if Maye isn't ready to go day 1, be depth, or play the hybrid S/LB role. Injuries happen also.
I'd think Gilchrist is gone, but you never know. Maybe they just keep him around as insurance until the last minute and then release him if everyone makes it through camp healthy.