I did a kind of sequence of the meetings Lambda could do:

1. Lisa and Rachel Alucard: This is more for the beginning. Both will try to take Lambda from Azrel.
2. Celica and Kokonoe: I suppose Celica's still under Kokonoe's watch. So this could make things interesting if they were to meet once again, except in Celica's case, it would be for the first time.
3. Noel Vermillion: The memory recovery starts right here with Noel, just like the Arcade. It doesn't have to go literally like the Arcade, so we can think on this.
4. Ragna the Bloodedge: And the meeting. Of course, Lambda won't go on a killing yandere spree.

I didn't included Nu because I probably won't bring her.