I can't see how Bergeron could go ahead of Shore or Esposito. I'd go with Orr, Bourque, Shore and Esposito.
I would assume that the case for Bergeron is based primarily on the thought that the current version of the Bruins, including the cup winning team of 2011, is worth recognizing and if this current era is included, there is no better candidate than Bergeron due to his individual accomplishments.
For good or ill Esposito becomes somewhat a victim of the greatness of Orr - and since Orr was so important (and rightly so) there is less room or need to include other player to represent that era.
I think that the case for McDavid shares some of the same sentiment. If we want to recognize that Edmonton has meant something outside their dynasty, all four players cannot be from the dynasty years. Had Tavares not fled the Islanders this summer he would probably have been the fourth (after Trottier, Bossy and Potvin) for the very same reason.