Listening to the Today programme this morning I couldn't quite work out what the names of the welsh children were, so I re-listened, Then I searched for more info.
About 46 mins in
I heard Osian clearly. I guessed that what I heard as Deia was Deio, but Gwenly, Gwenshie, Gwentchy threw me.
I'd seen Gwenchi on here and assumed someone was having a laugh, as it wouldn't be a pleasant sound. Ch is like the ch oin scottish loch, but if you say it as ck, it sounds like the word for weasel
The name was Gwenlli, which is a new one, possibly Gwen+Enlli. Gwenllïan is an old name and much nicer, and is usually shortened to Llio or Gwen.
Anyway, if you want an example of what a non Welsh-speaker made of the name, have a listen.
[https://www.bbc.co.uk/news/uk-wales-politics-56522989 link to related article]