A friend of mine who works for MAG’s Terminal team said they are looking into the development of a Fourth Satellite currently.
A little bit of other information they told me was that Taxiway Hotel has been extended to Taxiway Echo and the stands on Echo facing south will be finished soon meaning their will be more parking stands available, which would be needed for next summer.
Also the old hangar 4 site is/has been made into stands. Apparently for day stopping Cargo planes. Hope this helps some of you.