OK, the most basic list we need seems to be:
Peasant
Spear Militia
Bannermen
Axemen
Foot Knights
Cav Scouts
Knights
Archers
Xbows
Starks, Tullys, Arryns, Lannisters, Baratheons, Tyrells, Greyjoys, Wildlings, and the Watch can use BI's barb peasants. Spear militia would also be the barb version from BI, except for Martell. Halberdiers and Axemen for Baratheon can be any not-so-fancy versions from WHTW.
The halberdiers could be the ones with kettle hats that the Brets use? Are we wanting axe & board axemen for Baratheons or 2-handers?
The WHTW archers will do fine as the basic archery unit I guess. Foot Knights we could use the WHTW Reiksguard Foot unit?
Let's put off on Barath axemen for now. We'll use Bannermen in that spot and save axes for a special. Everything else sounds good.
What are the bannermen going to be - foot swordsmen of some sort?
And what are your thoughts on crossbows?
Aye bannermen are swords, something similar to the feudal knights in M2? The regular xbow guys should be fine.