There was a shot in the trailer when Sora was riding Baymax in flight, of a car and truck moving (YES moving) in the road, so at least some NPC's involved.
Also, I know this is farfetched as no one brought this up but from the previous trailer that was released last week and the trailer we got today does anyone think that Go Go Tomago is set to play a major role in the Big Hero 6 world besides Hiro and Baymax? Because in the previous trailer she was teaming up with Hiro and Baymax to defeat the Heartless on the San Fransokyo Bridge only to get injured in the process with Hiro making sure she's alright; in the voiceover it was Go Go who says that Big Hero 6 "Are a team and a team delegates"; the latest trailer has her commenting that the large Heartless "is the right size" and she is shown sitting on top of the San Fransokyo Bridge with Hiro, Baymax and Sora eating Chocolate Ice Cream Bars.