These are legit variations used in Ireland.
Yes, they're used, but no, they're not legit. They're mispronunciations.
The trouble is, @mathanxiety, if one doesn't accept anglicised names or anglicised pronunciations as legit in Ireland, half the country will end up nameless ( tiny exaggeration maybe 😅).
I do think there's a distinction to be made between Irish names that have an Irish root but have been anglicised (spelling and/or pronunciation) and Irish-language names. Kieran is an Irish name, but Ciarán Irish-language, for example. Brian is pronounced differently when you speak English and Irish, and most Nialls in Ireland use the anglicised pronunciation now. Similarly, I see Niamh said as Neeve as an Irish name, while recognising that it's not an Irish-language pronunciation, and that Nee-uv is.
I guess one issue is that people often don't even realise that the pronunciation they're using is so strongly influenced by English. In general, Irish people have a poor knowledge of the sounds of the Irish language (with the obvious exception of native and fluent speakers). Children learn both Irish and English in school from age four or five yet most are taught the phonics of only English, which is a piry, I think. I'd love if we could improve our Irish language teaching, but we can't change our history, and anglicisation is here to stay.