Well, basically they include all the MC in the live album, normally they never put it like any other Kajiura's live album but this time... the whole album is like audio version of the concert. They even include the last Lineup message and Ending.
Personally, based on characters I like Hikaru the most, I really like her singing style also, but recently she changed a bit, and Keiko caught my attention more.
They don't have leaders, only something like "front-men" or spokesperson which is either Wakana or Keiko, probably because of seniority (they work with Yuki Kajiura longer than Hikaru), I'm not sure though. And yes, Wakana is the most talkative, if you see blog posts written by her, it's very long compared to others
If you want to know the members more (including trivias), you can read this blog post:
All About Kalafina