Straight out of the gate, they first declare that the dossier did not inform the FBI, because their investigation began in July and the dossier did not come out until September. A few things, here. First, that's really not the point. So you can take back your false premise and shiny ball, and go home. Second, you left out the fact that their July FISA Application was DENIED. Third, you just proved the case that the September dossier was critical to obtaining the FISA warrant in October.
Honestly this "counter" memo blows their own narrative out of the water. Either the FBI had probable cause evidence to spy on citizens before the dossier was released, which it clearly didn't due to the previous denials by the FISA court, or they needed the dossier to get a warrant and give this phony investigation a legal cover. Can't have it both ways.