The cameras are powered by the DVR and do not come with a mains power adaptor.

Unfortunately the camera does not move around. However you can tilt and move the camera to your desired angle manually.

Yes they will work but they are standard definition so the quality won't be as good.

Yes, there is a VGA output on this unit.

The camera twin pack includes one additional power supply, which will power both cameras. The cameras and power supply both plug into the DVR, exactly the same way as your existing camera's.

The cameras must be used in conjunction with an existing Yale CCTV kit such as the Yale Easy Fit 960H 2 Camera CCTV Kit. The cameras will record to the DVR hard drive which is included with the CCTV Kit. The cameras do detect motion and installation will mostly involve screwing cameras to the wall and running cables from the cameras to the DVR. These kits are very much a DIY installation and there is no need for an electrician. The cameras are powered via the DVR which is plugged into a mains socket.