OK, I choose the additional condition of mythological names, plus different-letter middle names as that shouldn't be too hard! :)
DS (27):
Daedalus AaronDD & DS (25):
Daphne Belle &
Daire BrianDD (23):
Damayanti ClaireDD (22):
Danae ElizabethDD (21):
Diana FayeDS (20):
Damon GeorgeDS (18):
Diarmaid HarrisonDD (17):
Deirdre IsabelleDS & DS (15)
Devaraja John &
Deimos JoshuaDS (15):
Dilipa KaiDS (13): Diamedes
LukeDS (12):
Dionysus MarkDS (10):
Drupada NicholasDD (9): Dwynwen
OliviaDD (7):
Delia PennyDD (6):
Demeter QuinnDD (5):
Desdemona Rhian