It used to be my favorite name. I still really like it, but wouldn't use it. I love the meaning, I love that it's a palindrome and it has a nice sound. I also really like
Elodie.
Eirlys looks funny to me and I have no idea how to pronounce it. It goes well with
Xanthe and
Sylvie.
Xanthe and
Sylvie are both lovely!
The reason why
Aviva isn't my favorite anymore is because to me it has started to sound like a brand name. It now reminds me of medicine and cars for some reason. Or like something people say before they drink alcohol, kind of like 'cheers' or something (I think in Switzerland they say Vivai which could be why I think so).
I would choose
Elodie.
Elodie,
Sylvie and
Xanthe sound lovely together.
Aviva still makes a nice middle name.
Elodie Aviva is really beautiful.