He's the reply from Big Chris himself :
Let's see... checking the design docs, the way it should work is:
1. Visas and Handmaiden *have* to have their first fight, which requires that Visas have a higher influence with the player (by 15 points) than the Handmaiden does.
2. Then that opens the door for the Mira and Handmaiden scene, so Mira has to be in the party.
Hope that helps,
Chris