They wouldn't have to but if they did then it would be fine. If I was to have twin girls now (with my four kids already
William,
Alexandria,
Ruby and
Lucas) then I'd call them:
Evangeline Summer and Olivia-Grace
May (
Evie and Gracie-May)
If I was to have them with no previous children then:
Alexandria Iris Claire and
Evangeline Adriana Summer (
Alexandria and
Evie)