Cassandra,
Cassia, &
Charisse are girl names I'd favor, and
Toby would be interestingly unique yet charmingly casual as well.
Amaryllis &
Briseis would be welcome additions to the male repertory, bearing in mind that
Amaryllis may be nicknamed "
Mary" and that
Briseis may be nicknamed "
Bree" or "Bris". There would always be a few boys by the name of
Mary or Mary/Marie derivatives.
Constance is fine but I wonder about the possible nicknames of "
Connie" - otherwise "
Stan".
Carol is already somewhat of a common name for boys. My favorites are
Cassandra,
Cassia, and
Toby; as well as
Amaryllis (I would welcome this as a boy's name!) - as well as
Briseis:
Carol already is a great name for males.