I've loved it as a nn for
Persephone for years, although I prefer to spell it Seffie. It never occured to me to use it for
Josephine /
Josepha, but I can see it working nicely there too.
Seraphine keeps coming into my head for some reason. I know it isn't the cleanest of transitions, but I can also see Sephie as a nn for
Seraphine /
Seraphina. Do you agree or am I stretching it too far?