They were checking names at the door. He would already have made a commotion there if he forced his way in. There was no indication that he wasn't invited. He was a member of the Corleone family.
Yes, but it looked to me as if an 'inner circle' of guests was created. If you look closely there were those guests who were actually partaking in the inner room celebration....and then there were those, like the press, who were on the outer perimeter of the room looking in.
At least that's how I remember it. Been a long time since I watched it though, so I could be wrong.
