I can only help you with the last question. Brownies have the Small Stature feat, that aids combat versus larger opponents, but prevents them from using weapons of the size Large (this includes Longbow and Double-Bladed Axe), just like the Halfling race. Logically, Brownies should be unable to use even Medium-sized weaponry, seeing how they are half the size of a Halfling, but I think that's not implemented, seeing how you'd have to deal with some near-impossible hard-coding. Feel free to correct me on this one, however.