He could have picked just about anyone who worked there and said they passed by. And they probably did given the time and location and fact that many employees were heading out for the motorcade. Oswald had also worked there for weeks and observed the patterns of behavior. He would have know who had lunch where and with whom on a typical day. It would be no great feat to make something up. More importantly, though, who saw Oswald there? Old Ozzie was perhaps the most politically astute person in the entire TSBD workforce but he is not going to even bother to step outside to watch the presidential motorcade. The same guy who checked JFK's book out of the library to read. And the fantasy conspirators are going to trust the entire plot to frame Oswald to luck by allowing him to roam about the building during the assassination and not be noticed by anyone who could give him an alibi or even do the most likely thing that day to head out of the building in the company of dozens of coworkers, cameras etc. It is laughable.
He could have picked just about anyone who worked there and said they passed by. Yeah sure, except he described exactly those two individuals who were actually there.
And they probably did given the time and location and fact that many employees were heading out for the motorcade. The sighting happened at around 12:25 when most employees were already outside in front of the building. When Jarman and Norman entered through the backdoor there was nobody else there, at least they didn't see anybody there.
Oswald had also worked there for weeks and observed the patterns of behavior. He would have know who had lunch where and with whom on a typical day. It would be no great feat to make something up. Except this wasn't a typical day, so his observations would have been worthless
More importantly, though, who saw Oswald there?And pray tell, who saw Oswald on the 6th floor at 12:25? The answer is; nobody.... so your conclusion must be that he wasn't there, right?