There seems to be multiple opinions as to the identity of the man in the suit. Some have said it might be Gig Young while others believe him to be David Janssen (which is possibly related to the identity of the fragments of mistery film #2).
The last 2 fragments have been identified as "The Shoes of the Fisherman" from 1968. In the first case, Anthony Quinn is sharing the frame with Oskar Werner, who played fraille David Telemond. In the second frame, standing at the left is Burt Kwuok (as Peng) and, as previously stated, Anthony Quinn (as Kiril Lakota).
All these information came from the scholars at AMIA-L. My immense gratitude to them.