I am not sure if this is really going to happen. NY state building a new station for NJT and Amtrak? Sounds a little crazy to me.
There is no easy way to connect any of the new tracks to the tunnels going east to Long Island, so unless there is an unannounced plan for new East River tunnels, why is NY going to spend billions of dollars to build a terminal for NJT? While Amtrak has said that it will contribute money, NJ has said nothing. The new tracks also cannot connect to the existing North River tunnels, so until the new tunnels under the Hudson are built, the utility of this is zero. Cuomo will be out of the governor mansion before this has any chance to happen even if he runs for another term. This sounds more of a political posturing than a real plan to me.