Fantastic thread! I had wanted to watch those videos myself but have yet to find the time - thank you for summarising them all. It’s a shame the E4 posts devolved the way they did, but I’m happy the Pokémon community is so sceptical when it comes to questionable cards.
Just a minor Pichu-related nitpick:
These are all numbered in the same way as the official English release, 58/165 for the Pichu and 112/165 for the Hoppip. It is my belief that the holes in these were to physically attach them to Game Boy Advance e-Reader kiosks to prevent theft. There’s a thread about them here: www.elitefourum.com/t/any-information-on-these-cards/12600/1. It’s worth noting that there are actually two variants as well, one set which is glossy on both the front and back and the other which is only glossy on the front: one set may have been intended to be attached to store employee lanyards (I show the differences here).
One other thing: on point 5 you also mention another Pichu, but I believe this is the same card as on point 4?