Rhiannon - one of my favorites! I love how it looks and it has a beautiful meaning.
Anwen - Meh. I’m neutral on it, but
Annie would be a nice nickname.
Eirwen - “Air-wen”? Kinda unattractive, but not horrible.
Ceinwen - “Kien-wen”? “Sien-wen”? “Seen-wen”? I dunno.