Evidence that TM attacked GZ?
That GZ was the only one who had any injuries, minor as they were, is not proof that he was attacked. Multiple posters have already stated that GZ's MMA instructor testified that he was a totally inept fighter, so the fact that he lost the fight, and lost badly, does not prove that he was jumped from behind.
Why did the jury ask for clarification on the manslaughter charge? Because they were convinced that GZ was attacked by TM but wanted to stall to get an extra free meal? Because they were curious in some academic sense about criminal law?
Of course, even if TM threw the first blow how do we know he didn't do it because he was afraid the GZ was going to attack him? Other than. of course, that people engaged in self-defense only use guns to defend themselves?
There are a number of plausible scenarios, none of which is conclusively supported by evidence.