Bifur is the mandatory hero.
I recently played a dwarf deck through Moria, relying on Balin to do the cancelling of all those nasty shadow cards that can abruptly end your game. Needless to say, Steward of Gondor goes on Balin, which Bifur nabs from to play the Lore allies.
Oin is one of those heroes I never get around to play. In this deck, he is a good quester and provides the Test of Will necessary for Sleepless Sentry and Crags and whatnots. Since the deck is quite good at getting two allies out, I use his ability to get Tactics sphere for Axes and Battle Masters. Gondorian Shield is the only card that is a bit stretched thematically, but it is so good if you get it on Balin with Steward of Gondor, so I kept it.
The total number of cards outside the core + KD/DD, VoI/RM is kept to 5, of which 4 are Hobbit Saga allies, who I felt were appropriate to include.