I checked the file structure of the blu ray discs: all files in the stream folder and the png files in the other folders.

I didn't find any videos nor pics that don't seem like being part of the collection of interviews, short making ofs, 360° turnarounds, artwork pics.

It's either one of those short making of clips that is not featured through the menu.

Or the easter egg is online content that is not stored physically on the discs.

Or there are no easter eggs.

Boba Fett cartoon can be accessed if you follow the instruction from Bill Hunt in his review of the blu rays: http://www.thedigitalbits.com/reviewshd/bdreviews091611.html