#1.) He’s wrestled as Jon Moxley in WWE before
Believe it or not, Jon Moxley has made appearances in WWE before, years before he signed as Dean Ambrose. WWE has publicly acknowledged this before, using clips of him against Val Venis when Moxley still had long, strawberry-colored hair.
He appeared on Heat and Velocity on three different occasions, losing all of them. Nobody would have realized that they were witnessing a future World Champion.