TRACON Controller described an emergency event involving an Air Carrier that required an immediate return to the departure airport; the reporter noting a post event review revealed that not all ATC requirements were completed.

Narrative

Air Carrier X declared an emergency about 15 miles east of the airport. He advised me that he may have a fire in the back of the aircraft. I immediately vectored him towards the airport. I had traffic in front of him on Runway XXL which I broke out to make room. During this time I was also coordinating the information I had with the arrival coordinator and the TMC. All the coordination was completed off line. I initially cleared the aircraft for a visual to Runway XXL. Though I mentioned to the aircraft I was working on getting Runway YY; that is the normal emergency runway. I coordinated with the other Final Controller for Runway YY and he began breaking out his aircraft on that final. I cleared Air Carrier X for the visual to Runway YY. I then called the Local North position in the Tower and advised him Air Carrier X was an emergency and that he would be assigned the emergency frequency. I switched Air Carrier X to that frequency and had no further contact with him. Later I spoke to the FLM that was reviewing the emergency operation. He advised me that he listened to the tapes and that Air Carrier X never acknowledged the approach clearance to Runway XXL as I converged with Air Carrier Y. This is critical in order to comply with 7110.65 7-4-4 simultaneous visual approaches. I did not review the tapes so I cannot confirm nor deny this. Nor do I recall getting the read back from Air Carrier X as there was a lot of other things I was doing.