Have you gotten your gcms notes? Usually 2 ghost updates a few days apart indicate some movement on the file. Most people in the world where citizenship applications actually move would see a tracker update in the days after successive ghost updates. You've waited a long time with radio silence, so hopefully you'll see your Background Completed or get a test invite. Emails only come for providing instructions to take the test, fingerprints or additional documents needed, or oath ceremony details.
I've just passed 3 months after AOR April 5 and have not heard a peep. I'm expecting my first set of gcms notes this week, and am fearing that I am falling into the security screening black hole.