Point taken about the cowardice of assassins but you go overboard with the idolizing Bruce Lee as a fighter. Bruce Lee choreographed his own fight scenes in movies which contributed heavily to his success. He was an excellent fight scene director and his shots were done perfectly. He was also a very skilled and talented martial artist.

That said it is very likely he would have gotten past first tier in an MMA fight against experienced fighters. Kung Fu and Wing Chun are very artistic but are not dominant fighting techniques and never have been. And it is unlikely Bruce with all his talent would have ever been able to defeat Chuck Norris in the ring, although he shined brilliantly against him in the movies. Movies are not reality.