I never understood why he didn't just plead guilty to those extra charges. It was said at the time of charging that it was a means to introduce evidence of recklessness. He could have circumvented that by pleading guilty.
Although the Tasha's one I'm still doubtful about. I have read articles on the internet about the glock and it's sensitive safety catch. I think his ex-friend is as culpable, but OP has already said in cross-examination that he was equally negligent, so I guess he will be found guilty of that anyway.
The sunroof one, well it was either in anger, in irritation, or to wind up the cops. The witnesses are not in unison on this, but he should just have plead guilty to that.
Incidentally, if anyone is on twitter, I found an account that in February, long before the trial started, was making some claims, that now appear to be quite valid. CelestialMari is the twitter handle, worth checking out