Okay, it sounds like at least five girls are being "called," presumably at once. And none of them are the potentials that we've seen so far.

I say presumably at once because traditionally a slayer is not called until the one dies and this is only a one-hour show.

Since they are non-speaking parts and won't interact with the main cast, presumably, the show will end with a lot of girls being called as Slayers. Maybe even the potentials that are in Sunnydale if they survive long enough.

Also, we don't know what will trigger them all being called. It's normally happened when the Slayer was killed, but we can't really presume anything since this seems to be something entirely new. So even though new Slayers are being called, I don't think it's death knell yet for Faith.