I contemplate this a lot, since twins run in my family. I am a twin, but monozygotic (identical), which is not genetically passed. My grandmothers had twins on both sides of the family -so you never know!
Today, I would name them:
Nadine and
Joanne (Nin and
Jan)
Nadine and
Gerard (Nin and Ardi)
Gerard and
Blaise (Ardi and B)