After only two months and change, my first suggestion:
Female leaders of the far-future teen superhero group the Legion of Super-Heroes:
- Imra Ardeen aka Saturn Girl
- Nura Nal aka Dream Girl
- Projectra aka Sensor Girl
- Jazmin Cullen aka Kid Quantum
If we need a fifth, the Legion is due to elect a new leader in their next issue, and it's going to be a girl; we just don't know which one yet. (Possibilities include Kara Zor-El aka Supergirl, Tasmia Malor aka Shadow Lass, and Theena, who isn't a superhero at all, although she is a neat character and would make the best leader of the three.)
The new leader turned out to be Supergirl, or Kara Zor-El if we're going by civilian names.