John Fox didn't prepare his team for anything Seattle brought, he didn't even prepare them for the noise.
Pete Carroll's staff had the Broncos completely planned out, they even had a contingency in case Prater blooped that kick in the middle of the field on kickoffs, which they talk about around the 17 minute mark. Just like how Seattle had that "if they jump off sides" go route shot in the NFCCG, they had an automatic blocking scheme switch on the fly if the Bronco's tried to kick it a certain way, and the players were reminding each other of this seconds before that kickoff. That's why Harvin had such a huge hole to run through despite the kick being executed to perfection.