the breach in the walls between the universes probably is real

It could easily be; they've already established that the breach would destroy two universes, and what better way for a big bad to prove how big a bad he is? I'm just saying that we have no data for exactly how this is going to play out, or who ends up where when it's over.

My hope is that if Martha meets Sarah Jane, she'll be allowed to then appear on the SJA, giving Freema a triple-play.