Thanks for your continued research into this Charles.

Two things I thought might be helpful to note:
1) The eBay seller is using your analysis of the $5 being “smooth” as evidence of his being real (huge stretch but he’s making it) so I wanted to show another photo of the $5 at an angle with lighting that appears on PCF. As you can see it does have texture similar to the other denominations from the PCF fantasy buy ($5000 also included below):

2) For direct comparison here’s the pcf fantasy $5000 and below if the one being to be sold on eBay. Lighting is different but overall I think it’s similar enough for comparison. I will let everyone decide for themselves whether there’s a difference:

PCF fantasy:

eBay listing: