If I was you I would eliminate
Samantha and
Jacqueline. For the longer names you might be able to find an alternative nn you like.
Catherine -
Catherine is short enough to not need a nickname
Madeline -
Madeline is three syllables, so
Maddie might be harder to avoid.
Caroline - What about
Line, Caro, or
Callie?
Genevieve - What about Vieve, Viva, or Genna?
Nicolette - What about
Nico or
Lettie?
Gabrielle - What about
Elle,
Ellie,
Ella, Bri, or
Brielle?
Seraphina - What about Phi of Phina?
One of my favorite names is
Alice, but sometimes I wonder if people would call her
Allie, and I don't like
Allie. I have the same problem with
Julia, but I don't mind
Julie as much.