Dark Pit's specials are:
B - Silver Bow: Shoots an arrow, like Pit. Dark Pit's arrows are purple and I think they're faster but with less range.
Side B - Electroshock Arm: Variant of Pit's Upperdash Arm. Launches foes diagonally instead of upwards.
Up B - Power of Flight: It's Viridi's instead of Palutena's. Couldn't see any differences.
Down B - ???: I think those are Orbitars, but is an offense based move instead of defensive.
Final Smash - Dark Pit Staff: Shoots with his staff. Kind of similar to Zelda's FS, from what I know.