Bug, but I haven't really tested bringing them to the pool a lot. So I'm trying that soon as well. Since the developers have talked about adding a friendship meter that should help clear things up.
So 15 girls are planned? That's impressive. Any chance we can get some Avengers or is that the sequel? ;P
So 15 girls... we already have Laura, Jean, and Rogue. Storm is in the game so I'm assuming she's number 4. Cecila Reyes is in the game so she may be a 5th? If I can make a speculative list (since I imagine the developers don't want to spill the beans as half the fun is the reveal) These are in no particularly order.
Kitty
Jubs
Magik
Emma Frost
Mystique
Betsy Braddock/Kwannon/Psylocke (however the hell you all manage that)
That's 10 and those women are tied closely to the X-Men. Next is me more loosely speculating like an earlier post:
Boom Boom
Wolfsbane
Dazzler
Domino
That's 14. Next you could go with characters like Madelyn Pryor, Rachel and Hope Summers, or the Stepford Cuckoos. You know characters who are clones or similar to other characters who are or may be in the game. You could do ladies like Stacy X, Lady Deathstrike, Polaris, Marrow, Blink, Pixie, etc. Lesser known characters from the franchise.
Finally you have characters with history with the X-Men or ties to mutants like Captain Marvel/Warbird/Carol Danvers, Ms. Marvel, or Scarlet Witch.