The plot thickens;
After spotting a Neo-Cosmos Holo Abra on Reddit, I went back to check on my own Abra and Kadabra from the Alakazam ex Collection, as I distinctly (and correctly) recalled them featuring the Retro-Cosmos Holofoil;
Furthermore, all images I can find online of these Alakazam ex Collection promotional cards show a Neo-Cosmos Abra alongside a Retro-Cosmos Kadabra. Here’s a clear example image from an eBay listing;
This leads me to suspect that the use of the Retro-Cosmos Holofoil might have been intended as a subtle celebration of Kadabra’s return to the TCG … but does not explain my Retro-Cosmos Holo Abra or the use of both Holofoils for 151’s Holo Basic Energy.
Regardless of my speculation, it’s another interesting wrinkle in this saga. I wonder if Retro-Cosmos Holo versions exist of previous Scarlet & Violet promotional cards.