30 hours of Special Features in marketing language means the following thing:

6 movies a 2 hours, each with an audio-commentary, equals 12 hours of bonus features.

If they add another audio-commentary, another 12 hours is 'away'.

So in worst case: only 6 hours of footage besides audio stuff will be featured, spread over 3 BDs.

Btw: the official Blu-Ray Teaser is now avaiable in 720p:

Watch official Pinky Lightsabers in HD.