I like Elsa, it’s compact, feminine & lovely. Frozen may or may not have affected my feelings though, that it’s a little buttoned up & stern somehow. That’s not a bad thing I guess, don’t want it to be too cutesy.
The name Disney’s really done dirty is Ursula. I love Ursula & Ursuline, and the nn Ursie!
Another possibility is Elisabeth, Elspeth or Elsbeth nn Elsie.