Regarding the follow through, yes, it is also a byproduct of the stroke mechanics, and I agree what happens before contact definitely is the causal component. I used to think that one should not dwell on the follow through at all, from the point of view of developing strokes - but I changed my mind somewhere in between.
If one subscribes to the principle of initiating the pulling of the racquet up and across just prior to contact, visualizing the follow through is a very important cue for developing the right mechanics, and ensuring that the ball has the intended direction, flight, and spin. The intention has to carry over beyond contact into the follow through simply because it starts so close to contact. This is IMO, of course, and you are all free to have other opinions. I am not on a mission to convert anyone to my way of thinking.