That said, I'm not a geophysicist.
Melting that ice shifts a km-deep layer of ice from a fixed position above nearby sea level to being part of the liquid ocean. This means that it doesn't exert any gravitational pull on the ocean nearby, so the water-covered part of the globe becomes a little bit more spherical. Not much more spherical: The article says 30-50m on the coast of Greenland, which is a very small fraction of the earth's radius.
The 30-50m column of water is distributed elsewhere.
from the wikipedia entry for tides.
And the land rising effect is certainly there, its well known from our norther hemisphere where satellite measurements have tracked for quite a while now how i.e northern Europe still rises in comparison to the southern parts due to the not being covered by the ice age glaciers anymore.
Taking the core to be a point, the distance to the sea's surface would depend on factors such as
* The earth’s variation from a pure sphere (6,378.137 km (3,963.191 mi) at the Equator and 6,356.752 km (3,949.903 mi) at the poles) [0, 1]
* The local depth of the sea (up to 10,984 metres for the Mariana Trench [2])
* Tidal effects [3]
[0] https://en.wikipedia.org/wiki/Spheroid
[1] https://en.wikipedia.org/wiki/Figure_of_the_Earth
And correct me if I'm wrong, but the local depth of the sea should not matter, as water would fill the depth before the levels stabilized. But perhaps the local volume of the water affects the size of the effects of tidal forces and local land mass.