Zephta is new to me - there's a biblicl Japhta or Japhtha somewhere, though. (He might be a variant of Japhet as in the Ark, perhaps?)
But, I was at school with a girl whose name was Zephne, pronounced like
Daphne but with the
ZE instead of the
DA. Short E. It looks more Greek than not, but I've never seen a reference to it, nor did I think to ask at the time. (She was of South African English plus Afrikaans extraction, nothing more exotic.) Is she unique in the world, or has someone ever encountered another one?