Yes, I've gone back and forth in this discussion between theories of what actually happened, and the legalities regarding what can be proven. The Meyerses have wrapped up "reasonable doubt" in elegant gift wrapping with a giant bow on top and given it to the defense. The sketch that looks nothing like EN, the failure to identify EN, the later admission that they knew it was EN all along, the constantly changing narrative, etc. But I think much of that can be overcome by EN's story to his friends. I don't know Nevada's specific hearsay rules, but "admission against interest" is commonly one of the exceptions to the general hearsay rule and is commonly admissible in court. So to prove that EN was the shooter in court, a lot will ride on the credibility of EN's friends as witnesses. They seem credible in the affidavit, but that doesn't mean they'll necessarily be credible in court.
As far as a self-defense claim, IMO it gets pretty murky. As you pointed out, SYG doesn't apply when the person was the original aggressor. And IMO, once the 1st shooting incident ended and the Meyers car fled back home, that shooting incident was over. Then, when the Audi turned into the Mt. Shasta cul de sac, the Audi became the aggressor. So in theory, SYG wouldn't apply.
Except, since everyone agrees that EN was a passenger, he wasn't in control of where the Audi went, and that might throw an interesting monkey wrench into things. IMO, EN's "legal right to be there" wouldn't apply if he elected to chase the Meyers car once it fled. But since he wasn't the driver, he could make the case that he wasn't in control of where the Audi went, and therefore he wasn't the aggressor.
Right now, I would love to know if any cases have been decided, anywhere in the country, based on a SYG defense by a person in a vehicle that they weren't the driver of, in which the driver was being the aggressor but the passenger didn't want to. Or claimed in court that they didn't want to.
I'm picturing a taxi. You're riding in a taxi. The driver gets in a road rage incident with another car. The taxi driver is clearly the aggressor. The other driver pulls out a gun and starts shooting, in self defense. You pull out your gun and fire back -- also in self defense. One of your bullets finds it mark. It would be hard to claim that you were the aggressor.
Such a case would obviously have much more clarity than this case with respect to who the aggressor was. But such a case could also lay important legal groundwork for how SYG would apply in such a situation. I don't know if any such case exists. If it does, I haven't heard of it.