Panel 2: He posits the pretend cookies are chocolate chip. She says Uh-huh and tells him she's pretending it's a real kitchen.
Panel 3: She then goes on to point out the other fifties sitcom stuff they can pretend to do. You will note he is far more interested in what she has to say than anything the larger, stupider child has ever said.
Panel 4: He then thanks her for the tour of her house.
Panel 5: This makes her ask him if they can all pretend like they're a real family. If I were there, I wouldn't have the heart to tell her that's what they'll be doing for the next four or five decades.
Hypothesis: The reason Francie says that she's pretending to do something when we all know she'd say she's actually doing it is that Lynn cannot think like a three-year-old. Wrapped up as she is in her cocoon of Fooby groupthink, she allows herself to believe that everyone would think, act and speak as she would.