I love
Irene with three syllables, and find it disappointing that most
Irene people settle for two.
Irena is new to me, though I am familiar with
Irina - different origin, pretty well the same sound. If I used it, it'd be a mn and I'd think very seriously about spelling it
Eirene.
Bianca is nicer than
Blanche. I don't like it much, and the only one I've ever known has ruined it for me. But as a mn, why not?
Nadine seems flat and bland and dated to me - sorry! I much prefer the pleasantly floral Nerine.