My first instinct and preferred pronunciation is ee-VON, but I don't mind yih-VON either.
Gwen Elsabeth is a nice combo. Classy. Personally, I'd try to spice up
Gwen to make her more fun, but there is nothing wrong with
Gwen Elsabeth.
Three boys nappin', one mama namenerdin'
To peruse my top 100ish names:
http://www.behindthename.com/pnl/82589To peruse my non-name musings:
http://jodifriesen.blogspot.ca/