3 Re-rolls is more than enough for a team with so much Block, you may wish to drop a Re-roll and start with an Apothecary instead. Though saving up for one and a bench shouldn't take long. But 2 Re-rolls should be perfectly manageable if you wish to start with the added protection of an Apothecary.

Black Dwarfs really need all the MA they can get, so a second thrower really pays off. Only having 1 DF is fine, with that starting line up you shouldn't need much gold, just an Apothecary and relatively cheap lineman to fill your bench.