I wonder if these weren’t simply convention headshot commissions that weren’t turned over to be covers?
My best friend owns a commission that was done for him by an artist and then LATER made into a well recognized cover for Detective comics 1000. In this case both the original owner (because now it’s a published cover) and the artist (because they don’t have to put in effort to create the cover for a variant) are happy
I’d love to own the originals as that is my bread & butter (OA), but these being commercialized, digitally colorized hold absolutely zero desire for me.