Jane is great. Simple and elegant.
All your other suggestions, apart from Brooke (a surname, which I do not like), are short forms. I know not everyone agrees, but I think it's nicer to have a long name so that the child/later adult can choose. Rosie, Cassie etc are sweet and cutesy for babies, but I'd hate to be an adult without a more dignified alternative.
So
Cassie = Cassandra
Nancy = Anne, Anna, Agnes or even Annabel
Eliza = Elizabeth
Rosie = Rose, Rosa, Rosemary, Rosalind, Rosamund, Rosalie etc etc
Otherwise, if you like James and Richard, what about Jemima or Richenda? Or Margaret, Emma, Susannah, Diana, Alice, Mary, Helena...