Two comments, one quibble:
1) All sins of character, errors in science, awkward lurve dialogue, and logical weaknesses were absolved by the line "she looked as though she had added two plus two, and gotten... a green plastic fish". (feel free to fix that if you have the quote handy)
2) All of that imagination, and the color of a brontosaurus is "green"? He's pushing a time travel theory... he could at least see them in electric chartreuse, or paisley.
Q) I don't think it was spelled out, but they established that the femur was modern human through... DNA testing? If it was a modern human, there would be a lot one could tell from the results, without necessarily having to "match" the bone to a known individual. Of course, if you felt, as I did, that Stu thought the bone was his, anyway, couldn't he have done a quick test to see? Or did Stu not take any DNA to the office that day?