The selection for the Wings course for stage 1,2,3 is the same regardless of whether it is cadet or ATP. Some of the links posted above are relevant to anyone thinking of applying to CTC.
Everyone has to take pilapt and everyone has to do, if successful with the pilapt, an interview and group exercises. Of course questions in the interview will be directed at your flying experience and own life experiences.
Where things differ is stage 4. Cadets get a sim ride. The ATP stage 4 is the Airline Qualification Course.