My guess would be that somehow Will was not told or purposely prevented from attending the pirate council, Liz only being able to go because she somehow managed to get the Piece of 8 from Sao. I hope he's not bringing the whole EITC with him....
Here's a thought, what if this is close to the end and he has the locket as proof he killed Davy Jones? That would help both all the pirates and the EITC and would lead into what would have to happen next-- if Will has to take Davy's place.