Thanks for the GIF.
One brief observation again re the alleged limo stop (this has been mentioned before numerous times): You can clearly see as the limo slows down and Hill climbs onboard the LEFT tail/brake light appears to light up - it brightens - but NOT the RIGHT light (see image below). Only one light brightens; apparently from the sun shining on it. From this view then it seems that Greer did not step on or tap the brakes.
Of course this is where we hear from the conspiracy believers who proceed to read from Page #1 in their "JFK Conspiracy Manual": viz., "If you can't refute evidence simply claim it's faked and therefore more evidence of a conspiracy."