Make believe is fun, isn't it?
Obviously, because you make believe that Oswald carried a rifle in a bag.
Marina was in bed. Lee said goodbye to her. Lee left the house. How do you know that whatever Lee left with, he would have taken it into the bedroom with him when he said goodbye to her?
I don't. But you seem to think that it was impossible, or you wouldn't have considered "Marina didn't even get out of bed until after Lee was gone" to be a rebuttal to "Marina stated that she thought Lee took his lunch in a small paper bag that morning".