That's tough. I think it depends on how established the NNs are and if there are options for several NNs.
I love
Samuel but dislike
Sam , so I probably wouldn't use it because
Sam is so obvious. On the other hand I would use
Penelope even though I don't like
Penny, because one could create loads of other NNs for her and tell people that she is called that and not
Penny.
I hope that explains what I mean.
How about
Jo for
Josephine? I don't like
Josie either. I think
Pepita is pretty cool.
Josephine is a lovely name, I don't think you should hesitate to use it. She could be called many things.