It depends on the denomination and position.
I would hardly call a police or military chaplain a "deaconess". For one thing, they aren't all female, and for another thing, police, military, and hospital chaplains are supposed to be ordained, not laymen. The police and hospital chaplains usually perform in the role of counselor and comforter but they are also preachers. Military chaplains do everything that their civilian equivalents do.
If the chaplain is a priest, then "PRIEST" is an accurate sign to use. If the chaplain is a Protestant or Jew or any religion that doesn't use "priests" then the "PRIEST" sign would not be accurate.
I've never seen "PC" used except for a Windows computer.
I've never seen anyone use that sign.
Usually a "C-CROSS" on the arm refers to a medical clinic. It's an initialized version of "HOSPITAL".
See above.