IN: Which person is he?
Jackie Chan is starting to become like Chuck Norris, because he is getting close to the age that he retired in his career.
OUT: Jackie Chan

IN: Which person is they?
Customer Support fields the questions of their customers so they could receive immediate assistance.
OUT: their customers

IN: Which person is she?
Emily asked Anna to stir the pot, because she forgot to do it.
OUT: Emily

IN: Which person is they?
The separatists launched a surprise attack against the empire so they could be caught off guard.
OUT:
the empire