Ah Yes the Commsphere's most entertaining and most annoying part of the game. Annoying cause you can easily miss completion percentages. Entertaining cause some rather funny stuff happens while people are on camera.
The basic idea is to cycle through all the commsphere areas at least 2 to 3 times after each event in Chapter 4. This way you should be able to get all the scenes and hopefully not miss one. You also need to turn the camera and possibly zoom in on them to get them to talk.