OK, here's plan B. You just start a new network and seed it with a copy of the old block chain (to bribe old users into at least trying it out). No need for elaborate and potentially expensive takeovers. Then you advertise the new network as the one sanctioned by Your Friendly Government.

What does the OP's elaborate, hostile, expensive plan buy you over plan B? That users will have to opt-out of your branch, rather than opt-in? Is that wise PR?