I think the 'motor zoom' is the mode whereby the focal length of the flash tracks that of the lens, so the the subject is correctly lit. It obviously depends on a number of factors one of which is compatibility between lens, flash gun and camera.
The other question, I'm not sure about, but might be related to off camera flash, triggered ('servoed') by external means. This might be a load of rubbish, of course; hope somebody who knows will correct it if I'm wrong!
Ernie