Im sure Facebook would have hired another developer to continue the development of the app. Too many people now use it for them to forget about it. In relation to when push is getting released who knows? It will be a massive test for the Apple servers, as the amount of notifications per day must be huge.
Most of the issues people see in 3.x are server related. My guess is Facebook has several developers working on the server portion of the push notifications for 3.1. I doubt Hewitt was working on that part anyways (only the client interface to it).