Warning ahead of time. Likely to be a long post. I admit there is a bit of frustration when this subject comes up like this as if it's never been touched on, as I've been working with this stuff for almost 20 years, and so have other people, past and present. I have folders full of UK and European inserts, adverts, backcards, email conversations with collectors in other places, there have been several threads on here too...
The problem isn't that the info isn't known. A lot of information has been known for years, longer even than the Wiki has existed. We know a lot about the distinctions you mention. The problem is that the mainstream websites often don't include it.
The reason this info doesn't stick is that collectors from outside the US generally conform to the US names, US timeline, US definitions. They use terms like NSS and NBBE (which you also did, RoseNoire) which subordinate UK and European releases to the sidelines, rather than integrating them under their proper set names and release years. If people genuinely want to understand how ponies were sold in the UK and in different countries in Europe (or elsewhere), then those things have to be challenged.
I feel like there's also a possibility some of these ponies are labelled UK because my site existed and they were on it, and that's why there's that assumption, as my site goes back a long way. But I also had to challenge the assumption all ponies from Europe were sold in the UK so :/
I feel like the choice really is either use the US system and accept that no other country releases fit in this timeline, or stop using these generalisations, terms, names, and websites that promote errors. The fact MLPMerch is a European (Dutch) based site that lists "UK" ponies (including ponies also sold in Europe) under Nirvana is a case in point. People are using this site even though it's classification system is beyond weird if you're trying to use it from Europe. But I think there's much more that could be done from the European side. It's just not ever really happened. I think if you started asking US people to go look in two completely separate parts of a website for SS and regular Surprise, they'd blink at you and call you mad - but European collectors have to do that for 1985 Posey and 1986 magenta symbol Posey, because one is seen as "US" and one as "UK" even though...both...were sold...in...many European countries (inc the UK), through various different set releases
I'm going to tackle the Movie Star Ponies specifically just as they've been mentioned. (Noting that magenta Posey, mentioned above, is NOT a Movie Star pony, despite often being listed as one).
Movie Star Ponies were sold in the UK (with puffy stickers and without) as simply My Little Pony (albeit advertised as being from the film and sold in stores as Movie Ponies).
They were sold as Film Ponies (I don't know the exact translation) in Scandinavian countries but on English cards (without stickers).
They were sold in Belgium and the Netherlands on I believe bilingual cards.
In France they were on French cards and called Cine Stars. I think these releases had stickers. The French ones had North Star stickers with Cinestar written on them.
I am not sure what other countries may have had this release, but they are definitely EUROPEAN.
The Movie Star release consists of:Magic Star (CJ Pose)
North Star
Wind Whistler (pink and blue whistles)
Gusty (painted leaves, green eyes)
Shady
Buttons (buttons and stars symbol - probably sold across Europe)
Buttons (large buttons symbol - only confirmed at this point for France and the UK).
It was sold in 1987.
The other set that Nessa was talking about is the
Pony Friends set, which was sold in Scandinavia and in South Africa. This set includes Truly and Cupcake in their regular forms. It wasn't sold in the UK. I have seen some Trulys come up in Germany, but haven't managed to confirm they were sold there. The set also included
Cherries Jubilee (dark symbols, curly hair - European and SA release)
Posey (dark symbols, same as 1986 release)
Shady (probably same as Movie star)
Hopscotch (probably same as 1986 release)
It was also sold in 1987 on English language cards marked Hasbro UK. But not in the UK. (Confused yet?
Believe me that's the tip of the iceberg xD)
I think there is some thought that there might have been a different additional pony in the Pony Friends set. I can't offhand remember who it was in the catalogue...maybe it was Leikin who mentioned it in another thread...
In any case, I'm sure there will be others posting stuff on here. I know there are a bunch of really active folk from the Nordic region who know a lot of stuff about their native releases and have been hugely helpful to me in figuring out some of the sets they had that we didn't.
It's a lot more complicated than being able to just say, this was a UK pony, this was a EUropean pony...if you really want to go down this path, you need to be ready to deal with multiple continuities...
Finally, as a general rule, a lot of the same ponies were sold in the UK and Europe, especially in later years. But there are distinct releases and odd occurrences in many countries. I don't deal with the Nirvana side any more, I left variants alone a long time ago, but even in the mainstream there are some weird things that don't make a lot of sense. There are also a lot of ponies currently thought of as US ponies which were not sold in the UK but were sold in some European places (Italy had Mimic, for example). And even though in later years there's more conformity, if you look at and compare inserts from the same year from different countries, it's like playing spot the difference as to which sets appear and which don't between places.
But the information is there.
The problem is that people aren't really looking for it.