I think the six months of gloom thing is a beautiful story ... it's about how the world really is. There's a winter for every summer; you can't have all that you want and none that you don't, & all that stuff -
Persephone is more beautiful, imo, because it encapsulates a natural truth, not just a "happy-pretty" idea.
Persie, I'm sure, would be the first nn I'd make up. Sephie works too, but it's a little more 'precious' seeming - how it'd work depends on the person.
I'd be tempted to put
June with it. Would that be corny?
- chazda