Questions regarding Airport Arrivals?

You can't get to where the flight is landing. You are only allowed in the unsecure part of the airport, and your friend would have to leave the secure area to meet you. At some airports, there are food courts and things outside the secure area where you could meet. But at others, that will mean hanging out at the baggage claim or ticket counter areas. I don't believe there is any place to hang out around Terminal B, outside of the secure area. This also means that your friend will also have to go back through security for his next flight, so he'll have to make sure he allows enough time to get through those lines.

Unless I'm mistaken, you're not allowed to go through security to a gate without a valid ticket for a flight. If that is the case then your friend will have to come out of the terminal to meet you and then go back through security to catch the next flight. Depending on how far the gates are from the security checkpoint and how much time your friend has before the next flight that may not be feasible. Unless you just want to shake hands and go your own way your friend is going to need at least an hour between flights. If you plan to have lunch or something they are going to need an hour and a half or better.

Check his arrival gate and terminal before you go on the UA site. All you need is the flight number and the date.

Park in short term parking and meet him at baggage claim. He will have to go back thru security at EWR.

Before 9/11 a person who wasn't travelling could go through security and meet someone at a gate but that is not allowed any more. If your friend is an arriving international passenger then they will have to come out into the public arrivals area anyway. If your friend is making a domestic transfer within terminal B then they can change planes without going through security again. They can come out, meet you in the arrivals hall and then go back through security but they will have to allow extra time for that. Since 9/11 airport and the failed shoe bomber airport security has become very tedious and paranoid. The Arrivals area in any airport is well signposted and contains information boards/screens with the times of the arriving flights and whether they are late or not. If you go on line you can probably find a map of the airport.

You just will stand and wait for him at his terminal. Simple. And no, you don't need a photo I.D.

When you get to the terminal look at the arrivals board and it will tell you which gate you can wait for them.