About
Cassius and Cassianus: Cassianus would have been the surname of a boy adopted into the
Cassia family ("gens"). For example, if
Marcus Cassius or Calpurnia
Cassia adopts
Aurelius Pontius, he becomes
Aurelius Pontius Cassianus, or
Aurelius Cassianus, depending on the type of adoption. A girl would become Cassiana.
I definitely would avoid
Cassian,
Cassius, etc... because of the character in the play... but mostly because of the real guy who murdered
Caius Julius Caesar. He was a huge as*hole (sorry to say that about someone who is dead, but yeah...).
Last thing, if you finally name your kid
Cassian, don't call the second one
Brutus. :) :) :) :)