What does Advika mean?
A recent given name derived from Sanskrit advitiya / advaita, 'unique, matchless, without a second'. The root is genuine Sanskrit, but the name itself is a modern coinage, appearing in records only in the 2000s.
What does Ishani mean?
From Sanskrit ishani (ईशानी), 'mistress, ruler', a name of the goddess Parvati, consort of Ishana (Shiva). Well established as a goddess name.