An additional point: twins were and are considered to be special, in humanity in general, but also in mythology.

Leto in Greek mythology is a female, and Ganymede is a male. In Greek mythology they are not related. But both are both loved and cursed by the gods. I expect Herbert had some intention, in choosing these names. And had some fun playing with them, and subverting the original stories to his Dune narrative.

Dune is the story of Gilgamesh. Or Jesus. Or Lawrence of Arabia.

Or, more accurately, it is all of those stories.

The Song Remains the Same.