It is nice to see Cordelia appearing on your list. It is pleasant, not overly popular and fits the trend of revitalizing older names. Do you prefer Cordie or Delia as a nick name? Gwen, Abram, Caspar and Wesley are also great choices.
I think I'd resort to Delia / Deedee most often, though I like the idea of Codie as well. I like Gordon / Gordy for a boy so I have a hard time getting behind Cordy for a girl. And Cora doesn't fell natural enough.