You might find it odd, but I am rather enchanted by the photo of Amelia holding the mystery fruit. I like the photo, as is, even though you cited "light fall off" and vignetting as problems. From the viewpoint of a expert photographer with a keen eye, as you have, those might certainly be "problems" of a sort. But, from the viewpoint of someone with an untrained eye, I see much artistic merit in that shot! The uneven light is haunting, plus it serves to highlight the subject (the fruit she is holding). Barring the opening shot of the lovely Amelia, this is my favorite photo in the series!

Now, on to the mystery fruit... Much of my attention is divided during PYPT — as a Moderator in the server, I monitor the chat for potential problems as well as users who need assistance, in addition to trying to follow the conversation there and listening to the voice-chatter. When the fruit was discussed, it looked familiar, somehow, but I was unable to figure out why, or what it was. Looking at it again, now, under more relaxed circumstances, it reminds me of the raw fruit of a Brazil Nut tree, which I saw several years ago:

The above sample was on someone's desk at the local bank, as a curiosity that someone gave him. It isn't as smooth as the fruit that Amelia is holding, but the size is about the same. Did you find that fruit out in the wild, or did you see it at a market? I don't think that tree grows in the US. The fruit also looks rather like a walnut fruit, although I have never seen one so huge, so I rather doubt that's what it is. The shape isn't quite right to be a paw-paw, at least not if the backside is as spherical as the side facing the camera. So, Brazil nut fruit? Walnut fruit? Paw-paw? I'm not sure, but please let me know if you discover the answer!