I think there are essentially three parts to the Rambaldi endgame, and only one part was dealt with in Before the Flood.
1) The flood. 2) The sister prophecy. 3) The sphere of life.
The flood would be to rid the world of all those except the Rambaldi followers, and the sphere of life would...
Bear with me here, it's a little long winded.
Irina Derevko was definitely the head of the late organization we know as the Covenant. First there is the circumstancial evidence and then there are the little hints dropped in by the writers in Season 3.
In Season One, we learn that there has...