[Dann of Thursday]

Regarding the telepathic thing, it seems they all communicate over an open channel which means it could be possible for anyone to hear another's conversation. C.C. may have overheard V.V. speaking about taking Nunnally by chance (or because he wanted them to come to the island) and just informed Lelouch of it. Marianne also could have found out and told her.

Regarding the whole slaughter idea, we did see her getting burned in front of that Geass church, though that might have been because she was a witch.

And with the two planets, given their appearence in the opening and in episode 2, I have come to believe they are something physical and real to a point.

I've also been aware of the usage of feathers often with these sequences and that makes me think that some aspects of C.C. original concept of being an angel may have been kept in.