stonStark, if I recall correctly, then Dacey was the only of Maege's daughters to follow her south with Robb. Now from your questions here I'm not sure if you've finished ASOS. If you have not read ASOS in it's entirety, then you might not want to read what I'm about to write.
Spoiler!
When Dacey and Robb died, Maege was on her way to find Howland Reed, I think. Maege was to enlist Greywater Watch in Robb's assault on Moat Cailin.
News from the South to the North after the Red Wedding must be terribly confused or practically non-existent. Maege presumably is still alive somewhere in the Neck. Yet this news does not seem to have reached Bear Island. All that Bear Island has heard is probably that Robb and
all of his followers were slain at the Twins. I surmise that Maege's castellan and maester have urged the young Mormont girl to claim the title of Lady Mormont.
I must say that I've resisted the urge to read Jon's preview chapter.... so far. Hence, I might be missing some details here.
Orion, regarding the new POV... At first glance, I assumed the new POV must be Mel. She's a major player close to a king. She's shown herself to be the most powerful magic user in the series thus far. She clearly has a religio-political agenda. And with the reports of Davos' death in AFFC, we will be losing the ability to watch Stannis... unless Mel is the new POV to watch Stannis.
By the way, you can find the models, referred to by GRRM that might be the new POV, at
Dark Sword. As you can see Jon, Jaime, Melisandre, Sandor, and Cersei are the only named characters. There are also four unnamed characters from the Night's Watch.
The second choice for new POV is obviously Sandor Clegane. This may be one that many of us desire to read. Sandor for all his straight forward anger/hatred/brutality is somewhat of an enigma as to his ultimate role in the story. He's served the Lannisters. He's been in the Kingsguard. He's turned outlaw. He's wanted to kill his brother. Now he seems to have resurfaced at the mouth of the Trident in a monastery. His work and wanderings may take the place of Arya's POV by telling us the conditions of the average person in Westeros.
I'd like to raise the possibility of a third choice as well. There is a model for the Keeper of the Ravens from the Shadow Tower. Shadow Tower is roughly halfway between Castle Black and the aforementioned Bear Island. It is the NW castle closest to the Iron Islands. Bran recently passed between Shadow Tower and Castle Black... Bran is looking for a crow, do you think the Raven Keeper of Shadow Tower might help him? This is the man who gets the incoming information to Shadow Tower, might he know something of Benjen Stark's whereabouts? Could he know of Coldhands? Also, with Stannis stationed at Castle Black and the Nightfort, the wildlings must now go around the Wall and Shadow Tower lies on the west end where many wildlings have snuck by the Wall before.