Regarding the second unidentified man (in the white shirt/top).
This footage was taken on the sixth floor looking at the window between the stairway and the west elevator.
In the foreground we see Fritz listening to one of his men.
Behind them is the man I believe is Dougherty:
Mr. DOUGHERTY - Well, when the FBI men---I imagine it was who it was---he showed me his credentials, but he asked me who the manager was, and I told him, "Mr. Truly." He told me to go find him. Well, I didn't know where he was so I started from the first floor and Just started looking for him, and by the time I got to the sixth floor, they had found a gun and shells.
Mr. BALL - When you went up to the sixth floor, it was after they found the shotgun and shells?
Mr. DOUGHERTY - Yes, sir;
If it is Dougherty in the clip it must have been taken after the shells and rifle had been found.