I've met a couple girls named
Athena and a
Leocadia. We had a Casshius for a while, too, at the school I work at. I think they could work in modern day use. Just look at
Harry Potter (
Minerva,
Albus,
Severus,
Remus, Bartemeus,
Draco,
Lucius, Merope, etc.) and The Hunger Games (
Plutarch,
Cato,
Seneca,
Octavia, etc.) bringing them back into use. Your cousin's kid's name is a bit too much ancient Latin/ Greek for me, though.