I can’t say much about the others, but the Pikachu certainly is. I won two of them on Yahoo Japan three years ago for 1.55k USD. Graded one of them as a PSA-10 for my own collection (mislabeled as a regular 175/XY-P version, since PSA didn’t differentiate them in the past - I might one day send it in for recasing). The other one (raw, which I estimated as PSA-9 quality) I sold for 1k euros earlier this year to a friend of mine who collects Japanese Pikachu cards, although they are selling for around 1.5-2k USD each these days.
And I think you’ve got all of them, @mthursty . Or at least, I haven’t seen more. Can’t answer any of the other questions unfortunately, since I don’t know too much about them.
Also, for anyone who’s unaware, these Event Organizer stamped cards are basically the Japanese variant of STAFF stamped cards we have.
I will try to remember it when I send an update to @pokemontrader for the Index of Efour Articles, which I might do soon.
Greetz,
Quuador