How about using these terms interchangeably, say Sowbhagyatha for males (or something that is proper in Sanskrit -- Sangom may clarify), and use Chiranjeevi for females also.
Cheers!
Actually my friend's father ( no more now) used to address ladies with both Sowbagyavathy and Chiranjeevi. (He lived in Srivilliputhoor, Thenkalai Iyengar. a great personality. In one of the letters, he addressed my wife like that). I have no objection to address like him. The more well wishes, the better!
Cheers!