The price might go down now, but it's not worth it. It will still take a while for the feds to sell, in the meantime the price will go back up, and then yo-yo. But really the people who will buy these coins aren't going to be dumping them on the market. They are buying to keep the supply controlled and the price high. :-)
It doesn't matter when they do it. Right now is when we have the knowledge that they will do it. Although there is some question about how much. It will definitely be 29,655BTC, but it could possibly be as much as 144,336BTC.
It's getting priced in right now.
It's being auctioned, this is not the reason for current movement.