Audio is audio on the tape, it doesn't matter if it is from a wireless mic system, on camera mic, or shotgun mic, etc. [8D] As far as using a cheap camera as a deck, I might warn.... Why "dumb" down the footage, if you are shooting it on a good quality camera, you will be degrading the quality by playing it through a cheap camera when capturing it. The footage is only as good as the heads that are playing it. Also if you are trying to play and capture footage from various cameras, you will run the chance that the heads do not line up from camera to camera, and playback may not be possible from one camera to another, or it may have some other issues. While it can work as a cheap deck, if you are looking to do this for a living, I would look into a good quality Mini DV deck, it will be capable of playing and capturing footage from all brands of cameras without issues.