If one were to tail another aircraft's radar shadow not only one needs military pilot skills especially when flying in the night (when one can possibly only see the tail lights or wingtip lights only) but also have the communications systems in "ON" mode to receive updates on exact flight path of the aircraft ahead. Given that all such equipment were switched off - this seems too unlikely
Not true, the apparent turn at waypoint VAMPI is a perfect setup for a 45 to 90deg intercept for a formation join, just need to adjust speed and heading to allow for the join target being early or late.