There are some USA dumps that have normal UK English listed as language instead of English (USA) in USA:

Could anyone check if these are correct? or should they be using the English (USA) language?

This makes me question if there's really any use in having 3 separate 'English' languages, when they are all using most likely completely the same ingame text in different regions. Perhaps it would be better to just have one 'English' language and give it the world icon (after all it's a global language). It would be easier and it would make more sense I think.

Well, there are only 3 games having 2 dialects of English (1, 2, 3). According to the No-Intro Convention, "Language variations are merged and not listed twice (ex. US English, UK English)", so I think this rule could be used by Redump too.