Official images and story (in Japanese) have been added to the TakaraTomy site.
It also confirms the product numbers as TFC-A02 for Brawn and TFC-D02 for Starscream. (the second link has the wrong number for Brawn).

Story in Japanese.
Starscream page
Brawn Page
Order page for Brawn - giving us a release date of August 28th for 5940yen.
Order page for Starscream - for a release date of some time in August for the same price.