Ea have used their best experienced 3D artist to create Bruce 3D model from scratch, for all other character their bodies was scanned in to ensure authenticity, this was obviously not possible for Bruce Lee. Shannon Lee had an interesting workaround. In the 1960s, filmmakers made a mask of Bruce Lee's face for the movie Green Hornet and Shannon held onto it over the years. She sent it to EA and they were able to scan it to create Bruce Lee's face with a high degree of accuracy. According this new articke at gamespot.
Also I have a 3D render image of Bruce 3D model that was not posted for public:
