Allegra: oh dear. All I can think of is Leggy!
Calista: Lissie might do - like
Lizzie but with -ss-. I've known Lissie used for
Felicity, and it worked very well.
Juliet: I've never known a
Juliet who used a nn, which is funny now I think about it. But I did know a
Juliana once who went by
Jill; took me months to discover the truth. I think Jet is too much of a stretch, though I suppose there's always
Letty.
Sapphira would have to be Saf or Fee, or
Fifi.
Valentina could give you
Lynn, but that's even more dated than
Tina and
Val!
Seraphina looks like another
Fifi, though
Fina happens where I live.
Any good?