I'll answer your two questions with very simple answers. Oswald was not eating his lunch (no witnesses saw him ) but was in the 6th floor of the TSBD from where he shot three rounds from c2766 and killed JFK and wounded JBC.
Two TSBD employees entered the TSBD at the rear door at 12:27.... They were Junior Jarman and Harold Norman. They walked across the first floor and entered the west elevator and rode it to the fifth floor. Lee Oswald told Captain Fritz and FBI agent James Hosty that he watched Jarman and Norman as the traveled to the elevator.
Please explain how Lee could have watched Jarman and Norman as they traveled across the first floor if he was on the sixth floor???
The timeline for Norman's and Jarman's presence on the first floor is sketchy. Harold Norman said on his 12/4/1963
" About 12:15 P.M. on this same date, after I had eaten my lunch, I went to the fifth floor of the building to watch the parade of the President pass the building. Bonnie Ray Williams and James Jarman, who also worked at this building went with me. We took a position in the south-east corner of the building on the fifth floor and I was looking out the window which is closest to the east end of the buuilding overlooking Elm Street."
Bonnie Ray Williams said he ate his chicken lunch on the 6th floor and then "went down to the fifth floor, where he joined Norman and Jarman at approximately 12:20 PM." WR, page 68
Junior Jarman testified that Bonnie Ray Williams joined both he and Norman a few minutes after they had arrived at the fifth floor. WCH, Vol III, page 203
The best estimate was arrived at by the WC and places all three on the fifth floor at approximately 12:20 p. m." WR, page 68
As to Oswald's recollection on the first day of interrogation he said nothing about eating lunch with anybody. It was during the second day interrogation that Oswald claimed to Fritz to have eaten lunch with Junior and "a little short man whose name he did not know,". This is also the same version given by SSA Kelley in his report. (WR, page 626) In Brookhouts version (CE - 1988) Oswald's says to Fritz that "he had eaten lunch in the lunch room at the Texas School Book depository, alone, but recalled possibly two Negro employees walking through the room during this period".
In Postal Inspectors H. D. Holmes version of his interrogation of Oswald in the morning of 11/24 Oswald does not even say he ate lunch.
"When asked as to his whereabouts at the time of the shooting, he stated that when lunch time came, and he didn't say which floor he was on, he said one of the Negro employees invited him to eat lunch with him and he stated "You go on down and send the elevator back up and I will join you in a few minutes." (
here Oswald is probably referring to Givens). Before he could finish whatever he was doing, he stated, the commotion surrounding the assassination took place and when he went downstairs, a policeman questioned him as to his identification and his boss stated that "he is one of our employees" whereupon the policeman had him step aside momentarily. Following this, he simply walked out of the front door of the building. WR, page 636.
As can be seen Oswald changed his story from eating lunch alone in the first floor lunchroom on the first day of interrogation to eating lunch with Junior and probably Norman on the second to actually incriminating himself by admitting he walked down to the second floor after the assassination. Junior Jarman denied having eaten lunch with Oswald. This Oswald alibi of having eaten lunch with them can be explain by the probability of Oswald hearing Junior speaking to Norman as he was sitting in the 6th floor SN. The probability of this is further enhanced by BRW's testimony that the reason he went to down to the fifth floor after eating his lunch on the sixth floor was that he heard walking and the opening of windows just below him.