For Celica, I'm torn between three voices.
I like Laura Bailey's voice, especially her Saint's Row 3 voice, as at least one other person has already mentioned:
I also really like Colleen Clinkenbeard's voice as Erza:
This one is especially relevant as Celica is loosely based on Erza, though much less serious in personality.
Lastly, I like Ami Koshimizu's voice for Ryuko Matoi, though Erica Mendez is pretty good too:
For Ayane, its easy. The voice of Ryoka Yuzaki for Satsuki Kiryuin:
I like Laura Bailey's voice, especially her Saint's Row 3 voice, as at least one other person has already mentioned:
I also really like Colleen Clinkenbeard's voice as Erza:
This one is especially relevant as Celica is loosely based on Erza, though much less serious in personality.
Lastly, I like Ami Koshimizu's voice for Ryuko Matoi, though Erica Mendez is pretty good too:
For Ayane, its easy. The voice of Ryoka Yuzaki for Satsuki Kiryuin: