I know the whole grammar thing has already been settled, but it wasn't like everyone was sure about it. I do know what I'm talking about when it comes to grammar, so I thought I'd lend some aid. The comma in the quotations is unnecessary. It's a quote, not dialog. The two do not work the same.
For three, you CAN NOT separate two independent clauses with a comma. That is called a comma splice and is grammatically incorrect. They can be separated by semi colon or period ONLY.
For six and nine, while it is a complete sentence without the separated portions, removing them changes what the sentence means. Thus, they are essential and should not be set apart by commas. Obviously, you aren't trying to say people in general are Philistines or something ridiculous like that.
