Re the rainbows. Maybe then the answer is you had set 1 then the flutterbye set and maybe some US imports along the way to account for Starflower?
I don't know if the Starflower card exists in English. I have seen it in Spanish and often for German packaged Italian rainbows including parasol with 2nd year colours in the hair. I have not seen it in English.
The flutterbye one exists in English. The person I know with Flutterbye moc on this card said she got it from Australia. I have seen nc versions on French card and nc and Spanish on Spanish cards. And there is talk of hk ones on German cards but I am less sure about that one right now.
What I know for sure is we had none of them. We had set 1 and Wedding bells. Nothing else. But like Medley etc the ponies were all in our stories...
Edit to add: Given the track record over there of ponies on cards they aren't pictured on, Starflower could easily have been on the Flutterbye card too...just maybe later on.
I also feel like Hasbro somehow had a card problem over there. Although it seems more like they gave you more ponies than pictured, rather than cards with pictures of ponies you didn't get...so I suppose that's nice.