I always thought "The Stars Will Aid Her Escape" was a clever prophecy twist rather than foreshadowing. It's got a pretty obvious double meaning. The four stars move into the moon right as NMM breaks out, which they never really explained. BUT if Luna was trapped by the Nightmare's influence, then the stars aiding in her escape is referring to Twilight. You know, the one with a star shaped cutie mark who discovers the only way to free her with the Elements.
Not sure if it was intended that way originally but I always figured that particular dangling plot thread was resolved