IANAL but I am a legal librarian and we get trained in copyright stuff and I worked for a while doing copyright clearances so I have some knowledge.
Duration of copyright
The lyrics to the bands you mentioned would definitely be in copyright.
The I Ching and Plato would be out of copyright, but the translations might still be in copyright, so you might have an issue here (Johnny?).
It makes no difference whether something is online or not, it is still in copyright.
Now, actually using stuff:
There's a doctrine called fair use that says you can use limited amounts of other people's work for commentary, criticism, scholarship, etc. There are no hard and fast rules about how much you can use. In theory, there's a good case that you should be able to quote a line or two from song lyrics without problems. HOWEVER, practice is quite different. If you look at books that actually do quote song lyrics, in many, many cases they will acknowledge the copyright holders and say 'this quote used by permission'. So the practice is that publishers are seeking permission.
I second the suggestion that you get a lawyer (or talk to your publisher's lawyers) and clear it with the publishers of the song lyrics.
For quotes on websites, you're probably good if you keep it short and acknowledge the source - e.g. "on the website bluelight.ru, Sim0n gave some stupid advice about taking the drug ecstasy 'as long as you take it once a month or so, you're alright'. This advice is dumb, you should never take drugs". You might want to contact the website owner though.