Ask away, foreign names aren't obvious! - and it's always really nice that people are interested.
Gwen(n)an (f) - apparently from gwen + nant, 'white stream'
Tegid (m) - TEH gid - probably from teg, 'fair', 'beautiful', but given that this one's in N Wales he was probably named for Llyn Tegid (
Bala Lake), our biggest lake
Eilir (m & f, but mostly m) - AY leer, ay to rhyme with hey - it's an old word for butterfly & the only one I've ever met is male.