Well, there's some good news, too. The district council has approved the change of the development plan for the area (americans know this as a "zoning map"), and thus the building permit has been approved. The main thing holding the project back now is in fact that the main utility access road into the current Autobahn construction site runs right through that plot of land.
(Source: Miranda Meier quoted by the Abendblatt Berlin, January 6th)
The "Tagesspiegel" newspaper also reports: "The renovation of an old Railway underpass at the Sonnenallee had to be cleared, and additionally the A100 Construction Site was blocking the 3 hectar, completely sealed plot of land. The construction site at the Sonnenalle is due to be completed within the year 2018. The planning application is being prepared, and "detailed plans" are being prepared. The Estrel Management did not want to divulge further details at this time."
So it's not the A100 in its entirety that is holding construction back, it's merely just the part at the Sonnenallee.