During the flashback, when Toph points at Yakone in the restaurant, she has 6 fingers.
During the flashback, when Aang enters the Avatar state a second time, Yakone's hands are up in the air, yet when he lands on the ground a split-second later, Yakone's hands are at his sides before he is enveloped in rock.
Amon orders the Lieutenant to electrocute the box to knock Korra out. The box is made out of metal, and therefore a Faraday cage, which should protect Korra from any shocks administered to the outside of the box.