Gersen: The two previous ones were "re-release" / "remaster" versions, nothing tells us that they will release a "new" game on day one on GoG; sadly I wouldn't be surprised if DS3 end up being released Denuvo'ed on Steam for a couple of months/years before appearing here.
I really doubt that, Nordic seem to be fairly committed to DRM free judging by their various releases and upcoming games here.
I would bet on DS3 coming here day 1 or near enough. Nordic have already got a load of upcoming games listed here and consistently release old games they have acquired the rights to. I don't think DS3 is so big that it would be any different.