That footage (of "Ruby" following Wade) appeared only recently, and one has to be cautious about 'new' photos and films. It seems to have appeared on the Denis Morissette Youtube channel in May 2015 (if Youtube's dating is to be trusted). That was before our Bookhout-related work but after Maksim's original video.
The baffling thing about this is that the hair pattern on the back of the head in this 'recent' footage totally matches that of the 'Corridor Ruby' on Friday afternoon (but not Sunday Ruby or the garage shooter), and 'Corridor Ruby' just does not seem to be Jack Ruby. If you do a visual overlay with the real Ruby and 'Corridor Ruby' you get a reasonable match, but he completely lacks what you have called the 'essence' of Ruby (in the face). Very odd. From the back, with the correct aspect ratio, I could almost believe that 'Corridor Ruby' is the real Ruby, but as soon as he turns his head to the left or right, it's a different matter.
I did once wonder whether the TV image was altered slightly to cause doubt. In the early days I would have suspected that they would have wanted to make it look less conspiratorial ('Ruby stalking Oswald'). However, after the Garage Shooter work, it looks as if they have gone out of their way over the years to repeat the 'Ruby shot Oswald' mantra until it gained nursery rhyme status, so they might be happy to have this image considered to be Ruby.
If the Midnight Press Conference back-of-the-head Ruby image is legit, and this guy was an impostor, we also have witnesses who place 'Ruby' standing on the back of a chair in the right-rear corner of the Assembly Room. Then again, one of these same witnesses, Sam Pate, could not identify Ruby in that famous Assembly Room photo when asked in Court. ('Ruby' in glasses.) I am suspicious of the old footage of Ruby at that press conference, despite the fact that somebody back there did heckle Wade on the Fair Play for Cuba Committee and Wade looked over to that corner - and pointed to it again on the Sunday night when questioned by reporters.
This forces me to suspect that both Ruby and an impostor were present, but would they have dared to use an impostor on Wade, knowing that Wade would probably see Ruby in court for days on end in 1964?
Linda Zambanini (like Denis Morrissette; RC) has said that 'Corridor Ruby' is not Jack Ruby.