You posted the film snippet. You tell me what we are looking at. Or is it possible You have absolutely No Idea as to the When, Where, or Who filmed this?
I've already told you what we're looking at, Mr Storing------------Mr Bill Shelley just inside the Depository front entrance on the afternoon of 11/22/63!
Your desire for it
not to be that is leading you to throw bizarre 'observations' at it ("fog drifting down", "TSBD Open House", "line strewn out the door") in the hope that some alternative possibility might stick. Next you'll be wondering about the coffee that's being poured. ('How do you Know it's coffee? Maybe it's boiled Coca Cola.')
Who, apart from Mr Shelley, do you think we are seeing in this footage? Members of the general public?