Based upon the spoilers in this thread:
http://www.dakkadakka.com/dakkaforum/posts/list/460695.page I've put together this Morvahna list.
The theory is that the Woldwrath provided the big hitting element to this list as well as buffing the magical attacks for Morvahna and the Druids. Morvahna herself does nothing for the Woldwrath. Druids would have Regrowth cast on them and would be used to pull enemies into attack range for the Woldwrath. The Shifting stones would stay in
B2B with the Woldwrath to heal it and would probably have Restoration cast on them or the Skinwalkers.
The Woldwrath can also shoot the Electricity immune Druids of Orboros to put two 3" templates on them to prevent non-reach one wound infantry models charging them.
Morvahna the Autumnblade +6
Winter Argus 5
Woldwrath 20
Druids of Orboros + Druid Overseer 9
10x Tharn Bloodtrackers + Nuala the Huntress 10
5x Warpborn Skinwalkers 8
Shifting Stones 2
Farrow Bonegrinders 2
50/50
[edited list in light of new information on rules interactions]