I like [name_f]Delia[/name_f] for you [name_f][/name_f]- sweet, bright and unexpected.
[name_f][/name_f]Nicknames could be: [name_f]Dee[/name_f], [name_f]Dia[/name_f], [name_f]Lia[/name_f], [name_f]Dilly[/name_f], Dizzy, [name_m]Del[/name_m], [name_f]Della[/name_f], [name_f]Edie[/name_f] (Dusty could work when you combine it with Augusta)