Can they be used to refer to a single person?
Yes
What if the person is of unknown gender or is a known person who rejects gender labels like he and she?
Yes
Or is he the generic pronoun in all (or most) cases?
Not for me. I use “they” as the generic now
Is the reflexive themselves ever used to refer to one person? Or would you use the singular themself, which doesn’t appear in most dictionaries? Would you use a singular themselves? Or would you go with the generic himself?
I’d use themself.
So if people just use who anyway, and if people commonly misuse whom, what’s the point of keeping it around?
None of your examples seem stilted and formal to me, they’re just how me and mine speak.
Let’s start with the biggie–can you end a sentence with a preposition?
Yes.
Also, do you consider particles to be prepositions
No. But then, I also speak Afrikaans, which is lousy with clearly non-prepositional particles, so I’m used to them.
Next, do you say on accident or by accident?
By, and the on construction grates on me.
What about the construction try and (Try and lift this?) Shouldn’t it be try to?
I’m fine with both.
And lastly, are there any weird prepositional uses that you’ve noticed?
Not really.
[“A while or awhile”] Have the two forms become synonymous? Personally, I think they have.
Not for me.
Is alright a word? If so, how does it differ from all right?
Yes, it’s a word, and it’s synonymous with OK. or Okay, take your pick. It’s not always the same in sense as “all right” but can be.
In a series of three or more items, is there a comma just before the conjunction?
Only if there’s going to be ambiguity. If it’s a bare list, like “Pick up some milk, cheese, bread, coffee and sugar” it is unnecessary.
Is the construction _______ is comprised of _______ horribly, totally wrong?
I don’t object, although in your particular example, I would just go with “has”, because albums are always made up of multiple tracks, so there’s no need to delineate multiplicity.
Some people might not pick up on the subtle difference because I haven’t heard this bit of guidance in years and years: “Don’t use a lot–use a great deal, instead.”
I think it’s ridiculous. Were any of the rest of y’all ever taught this?
No. Although a lot has associations for me.
Do you consider the two terms to be interchangeable? Are they definitely different? Can flaunt be used for either, but flout always has one meaning?
Different, and I would not use flaunt in the second example. John is flaunting his disregard for the rules, not the rules themselves.
Is it okay to write John could of won if he’d tried harder? Can of ever serve as an auxillary verb?
No, it is not OK.
I say “write” because there’s not usually any distinction between could of and could’ve in spoken English. They sound the same.
In your dialect, not mine. The vowel in of is not elided enough to make them the same.
BTW, I hated the format of the OP, it made responding very time-consuming.