Yes, the Japan Rail Pass does cover travel on the Akebono sleeper and yes you can use your rail pass with the Goron-to-shito, nobi-nobi beds and also reclining seats where available on these trains. You may find this link on using the JR Pass with overnight trains, this experience of the goron-to-shito car and these details of which sleeper trains can be used with the Japan Rail Pass helpful.
You must reserve your place on the Akebono however, so make sure you reserve well in advance if that is how you intend to travel.
Please note that the Rail Pass does not cover a sleeper car room, so if you want to use one of these you will have to pay extra room rate.
Hope this helps!