wrt to fg's question: Aren't katabatic winds fairly common coming off of GIS? Wouldn't those be cold enough to (re)freeze coastal waters?
Also, isn't the water just off Greenland quite 'fresh'/less salty because of all the melt from GIS, so it would freeze more easily?
This misunderstanding of anabatic (upflowing) and katabatic (downflowing) winds seems to be quite common. As air rises over a mountain range (or ice sheet) it cools due to a fall in pressure. As it descends on the other side, it warms up again due to increased pressure, so the two effects cancel each other out. This is also called the adiabatic process and is what enables fridges and airconditioners to work.
What seems to happen quite often in Greenland is a foehn (or chinook) wind, which is caused when the rising air is humid, causing precipitation and release of latent heat, with the result that once the air reaches ground level again it is actually warmer than before. This can quite often be seen along the north coast of Greenland in Nullschool.
When air blows over a large stretch of ice it will lose heat to the ice, so in the case of Greenland ice sheet, dry air that does not experience the foehn effect will presumably be somewhat colder on theleewards side.
As for meltwater runoff from Greenland, the major part of that happens during summer. Almost all the major sources of runoff face the East Greenland Current or it's extension, the West Greenland Current, and any runoff is carried away fairly fast and effectively disappears in these two currents and is nowhere near the Arctic by the time refreeze kicks in.