A 3.30pm Wall Street meeting is certainly doable from EWR if all goes well. However, on one occasion, when I was aiming for a similar schedule to yours, I found myself pulled over for 'secondary immigration inspection' at EWR. This is a large and unwelcoming room filled with the flotsam and jetsam of the world's peoples and feels like Guantamo Bay Junior School. I was delayed an hour in there and arrived, frazzled, ten minutes before the end of the meeting

BTW My impression was that the border guards at EWR took exception to my frequent one night (or even day) business trips to the US. Despite its size, EWR is a relative backwater - I think the guards at JFK are more used to people running lunatic schedules.