But when the time-shifts happened (purple flashes, nosebleeds, etc....) the entire island time-shifted, didn't it? It wasn't just a "who's in the range of fire" kind of thing. And the time-shifts were triggered, presumably, by the donkey-wheel being turned, which "disturbed the light" or whatever. And the last time-shift was triggered when Juliet hit the bomb, which also "disturbed the light," right? (Because the site was above where the old donkey-wheel was -- we saw it in the x-ray or whatever that Chang did.) So I'm assuming it would function pretty much like turning the donkey-wheel, and the whole island would time-shift. (Do we know what "time" it was when they ran into Rose and Bernard at Camp Happiness? I've totally forgotten...)
But wait, I think I see what you mean -- do the people themselves time-shift, other than the Losties that are presumably "special" because they're Candidates or whatever. Because there weren't any leftover Dharma people (who were back at New Otherton when the bomb blew) who shifted to 2007, so would Rose and Bernard have shifted? OK, I see. (But Miles shifted. He's not a Candidate, is he? He was "in range", but then so were several Dharma guys working at the site, weren't they? Hmmm. My head is starting to hurt again... and I think I need coffee...)
Anyway. TPTB said we'd see Vincent again, so I'm hoping they stick to that somehow. I don't think Vincent was Smokey, but I suppose it's possible he could see the ghosts. (You know what they say about children and animals and how they have a closer "connection" with the spirit world because their minds aren't all clouded with ed-yoo-cay-shun and cynicism and stuff...)