WDYT?
I love the nicknames [name_f]Gwen[/name_f] and [name_f]Winnie[/name_f] and I love the sound of Gwenllian! I think it sounds so magical. Sibs would be Senia, [name_f]Apolline[/name_f], Theoden and Hesperia.
I like it! Has the same fairytale vibe as the other kids. I’m surprised there’s no entry yet, it has approachable nicknames and feels current. Could it get confused for [name_f]Gwendolyn[/name_f]? Yes, but that’s not really a common enough name either for me to see it happening often.
I really like Gwenllian and [name_f]Gwen[/name_f] is so sweet!!
I think Gwenllian is lovely, and sounds nice with your other children’s names.
My only real concern would be that the ‘ll’ sound is likely to be difficult for non-Welsh speakers, but that might not be a problem where you live.
I love Gwenllian, it sounds so fairylike, elegant and quirky! And it goes so beautifully with your other children’s names. I don’t think it’s very usable in most countries though, as many English speakers (myself included) can’t pronounce the double L. If she went by [name_f]Gwen[/name_f] or [name_f]Winnie[/name_f] all the time and was only called Gwenllian at home/on the birth certificate that would be fine, but it seems a shame to give her such a beautiful name and then not be able to use it half of the time!