I love the name
Olivia but only as feminine for
Oliver and forms of
Alfher and Áleifr (see
Olaf) not as 'olive'
I don't like Ellyn, the y makes it look masculine (like in the Welsh names ending with 'wen' and 'wyn'.
Wen is stricktly feminine and
Wyn stricktly masculine)
Ellen is just fine.