I flew from Cancun to JFK about a week ago on American Airlines in first class with a friend. We waited in line for about 10 minutes for checkin. We chose to go to separate checkin agents, The agent that I went to was very quick, but my friend’s agent took five minutes or more to process his check in.
You won’t be able to get your boarding pass in app, and there are separate check in areas for people who used VeriFLY.