Most likely she saw a small bouquet of chrysanthemums on the seat beside Jackie and interpreted it as a small dog as the limo moved past. I cut her some slack on that one.
[soapbox]
But as I said before, Jean Hill's worst enemy was Jean Hill. Her problem was she kept adding to her story, but only after she read something new. Then she 'remembered' seeing it. For example, her initial statements never said anything about seeing anyone on the knoll (in fact, she denied it in her TV interview broadcast within the first hour after the assassination. Asked if she saw the shooter, she answered with a 'No'). But years later, after Gary Mack and Jack White colorized the Moorman photo to illustrate the supposed badgeman figure in the Moorman photo, Jean Hill 'remembered' seeing a cop shooting from the knoll. A few years later, when Roscoe White's son (no relation to Jack White, at least, not DNA-wise

), said his late dad was the cop who shot from the knoll, Jean then 'remembered' the cop she saw was Roscoe White. Etc. Etc. She is the female equivalent of Ed Hoffman (or more accurately, he is the male equivalent of Jean Hill, as she came first).
But that's a point for Robert to consider. How much of what he considers irrefutable eyewitness evidence is, and how much isn't. People see something in a flash, not focusing on it, and then later, interpret it as 'it had to be' this. But it was actually something else. And sometimes they add to their story (consciously or not) because they are influenced by what they read, hear, or or see.
Robert considers only what the witness said, and ignores anything the witness said that he doesn't like. He makes no attempt to fit the disparate pieces into a coherent whole. He doesn't consider that 33-year-later testimony might have been influenced in a number of ways, and might not even resemble what actually happened any more. He just takes the good bits he likes and throws those eyewitness statements out there as if they prove anything with no regard for anything like mutual corroboration or how the pieces fit together or whether there's any material evidence that supports the claim.
[/soapbox]
Hank