4 months seems the be the average for receiving notification for inland, and 2 months seems to be the current wait time for AOR/SA for outland. It really depends on which application is being discussed, as there is quite a difference in processing and wait time.
I'm not sure who wouldn't receive AOR or UCI? Everyone who submits an application into immigration receives a UCI at some point, it is how CIC tracks information on the specific person. If CIC doesn't have a UCI number for an applicant, then i would suspect they don't have their application or it hasn't been opened for processing. As stated above, the length of time it takes to receive notification from CIC varies based on the TYPE of application submitted.