The Feds are sure to be gunning for him yet because Chairman Xiden and the rest of the neo-Bolsheviks in charge can’t afford to let Winston get away with so much as a single act of self-reliance.
You are correct, the feds will some sort of obscure laws to charge him with, or probably some sort of civil rights violation. Even if they can't make it stick, the persecution is the punishment. Better chance of getting some sort of conviction with a federal jury, as the DOJ will make sure the jury pool is full of the "right" people to get a favorable seating of a jury.
A federal trial will be a political trial with DOJ guaranteed outcomes.