The second video you have a reverse pivot and that can cause you to swing OTT. You also loose your balance on the follow through. The chicken wing is not as bad as the first video but you need to work on that also. Can you get a DTL and a FO with you entire body in the video.
What mark is showing with the racket drills will only produce a push slice and a pull hook. To hit a fade the face is closed to the target (open to the path) and the path is to the left, to hit a draw the face is open to the target (closed to the path) and the path is to the right.
There is no boogie man in golf...lol. Flipping is when you lose lag pressure and that is what causes speed and "compression" of the golf ball for maximum distance and that back spin that everyone is after. The most important thing is that it will produce a more consistant ball flight for distance etc.
Here is how I see it. Shifting the weight forward while rotating the hips open allows the club to naturally come from the inside and eliminate an OTT move. It is also a more powerful and repeatable move.