Not too many red-headed men in Dealey Plaza. And not too many folks walking with purpose away from the scene. I think the probability that this is Mr. Shelley is strong.
If it's him, then we can start with his same-day affidavit:

All true, except he's left out a little southwards excursion he took beyond the hot zone in order to dispose of whatever it is we see him carrying in Hughes.
I think this is Mr. Shelley just after the shooting, carrying something(s) away from the scene:

And I think he--------and NOT Ms. Pauline Sanders----------is the person standing on the landing behind Mr. Oswald in these earlier Hughes frames:

We are seeing his head just over and behind Mr. Oswald, and we are seeing his jacket and head reflected in the glass.
If so, then Ms. Sanders only moved over to the west side of the landing in the seconds after the shooting.
This would mean that the ONLY people who would have had the flag-waving of Messrs. Oswald and Lovelady in their sight-line were
--Mr. Bill Shelley
--Mr. Buell Wesley Frazier
Everyone else's eyes were fixed on the motorcade