Those stations won't cost very much.
From what Metrolinx has been saying, it's looking like a lot of those stations won't be happening anyways. They've really been emphasizing how similar RER and ST are, to the point of saying that SmartTrack is unlikely to perform significantly different than GO RER in their studies. Munro's analysis also throws cold water on the idea of new stations because of scheduling conflicts with GO express trains. We'd be lucky to get a few stations out of this when it's all done.
We should wait until the ST studies are complete before making a judgement. But Metrolinx's comments sound really, really bad for ST proponents.
Honestly, this is kind of the worst situation. I think SmartTrack is a bit of a joke, considering the GO RER plans (which I support), but the infill stations are needed. It was obvious that Metrolinx had no interest in well serving the outer suburbs of Toronto, and now it is even more obvious that they aren't interested.
I get that it's technically difficult, but it really would be a major loss for Toronto IMO.
Getting back to Yonge North, it seems obvious to me from this report that the Province/Metrolinx is going to use GO RER and the TTC's ATC installation as an excuse to delay the DRL yet again. SmartTrack is not the magic bullet solution, as we all expected it would not be (Personally, I never understood how it was supposed to relieve the Yonge Line).