If I recall correctly your 5man group is 2 Pally, 2 Locks and a Mage. Are you also planning on a Horde group and if so what?
You point about having lots of the opposing faction to farm is something also mentioned in this video:
https://www.youtube.com/watch?v=gn9N8jYCqv8
I am haven't found anything that really gives any insights into the choices available.