1- Only if the card says so. ie: "Exhaust this character..."
2- The act of committing a character to a story exhausts the character (unless special conditions are applying due to a card effect). Once a character is exhausted, you can't execute an action that says "exhaust this character to" because the card is already exhausted. However, most responses, for example, don't require the character to be exhausted.
3-The most obvious use for Freelance photographer is that you could exhaust and commit him to a story on your turn. Unless you win the arcane struggles on the stories, your characters don't ready afterwards. So after everything resolves, now its your opponents turn and soon they reach the story phase and begin committing characters to stories. You want to defend but all your characters are still exhausted from your turn. If you still a an unspent domain with at least one resource, you could spend it now to ready Freelance photographer and assign him to a story your opponent has assigned to. (such an action would re-exhaust the photographer, but he would now be a part of the resolution of the struggles there this turn.)
Edited by Mike Eldredd, 05 May 2014 - 10:29 AM.