And Nunnally just killed all those Britannian in the Britannia Capital with FLEIA.....

or was it Schnizel's doing using Nunnally's name.

What I see here is Schnizel just using Nunnally as puppet in his fight with Lelouch and both Nunnally and Lelouch will end up as "mass murderer"

Celestial Being supposed to come in to stop the war between Lelouch and Schnizel, but I guess they will arrive 1 week too late.....

I thought Marianne (in Anya's body) did called out CC real name.....

which is Karen/Kallen

Go and watch that episode again.

Try Episod 20 around 20:30 to 20:38. Marianne did mention the word "Karen" at the end of her sentence when she speak to CC. My Japanese is bad, but I'm think that word is a person's name.