Regarding The Schuyler Sisters as the final number. I am guessing the producers of the awards knew Hamilton was going to take the big prize; however one of the major themes of the song is a celebration of New York City. Looking in from the rest of the country Broadway itself is a uniquely New York thing. Shows may start elsewhere or disseminate after, but having a show play on Broadway is the goal for almost all of them. It then makes sense to celebrate the City. In that moment everyone in that audience on that night that honored the best in theatre and shared it with the millions around the globe felt like New York was the greatest city in the world.

Ive just found this podcast- It's great! Let's go bingelisten to all of them!