cdev I will read your stuff (and notate some of that chemical info), just too much right this minute, what with Monday morning doldrums, thanks.
I did notice, a bit confrontational, at the neighbor's door, EXPECTING him to open up, and, OP, according to your rules, 8:30 am being slightly early for many folks, such as emergency workers / fire department, etc. More like 9:00 flat, especially for those 'repeat' expectations, that he just 'open up' his door.
I used to do more of that confrontational shit; essentially doing cover, for Property Manager's job.
Never comes out good, unless a person is certain that there needs to be aggressive engagement, but then that almost always requires a 'third cool head', like your Apt. Manager to take the reins.
I mean, perhaps you can arrange a short move, across the way, or get a unit in next building over, using same property, with all of that keeping out of (that one neighbor's) business.
The mental health aspects, also often relates to age and experience. Like, I learned; don't get confrontational, with a Meth user, (they tweak easy).
But living in San Leandro, I've learned, you gotta extend a ton of 'extra' respect. We have a neighbor, kid has some issues, with aggressive play / constant screaming. I just think, 'One of us...a member' of the human race.
Get your requests to landlord documented, if choose that route, but that's not your war, there!