Well, those are themes that can be extrapolated from the PD. However, I got a very different point than you in a number of areas:
I mean, the very first, most important piece of the PD in my opinion, can be found with our first obvious numeral V: "A Discordian is Prohibited of Believing what he reads." That statement, I think, sets the tone for the rest of the book. At that point, any reader who believes the writers mean what they're writing, might need to think some more. That is enough to warn me that any theme, or meaning within the PD appears to depend heavily on the reader. The reader must now decide for themselves, what to accept and what not to accept... and how tentatively to accept it. Ergo, a description of the PD that attempts to explain it without the use of ePrime (or some other "this is just my lame ass opinion" type language) appears somewhat incomplete and maybe just plain silly.
"A jug of wine, a leg of lamb, and thou! Beside me, whistling in the darkness" the meaning of life summed up neatly: Enjoy life, enjoy friends, have no fear.
Whistling in the dark has often been a euphemism for not knowing what the fuck was going on. It also has been used to indicate someone is nervous, afraid or uncomfortable (the lonely person walking down the dark streets, whistling nervously to look calm and with it). It could be interpreted in the manner you stated, but I'm not sure that Kerry would agree with your summation of that lione.
This book will drive you mad. Or at least make you maddening to others. The warning is on Page 5. A man dares to seek great wisdom. Some people see him as a holy man. Others think he is a shithead. Upon realizing this, he is enlightened. The moral of the story? What do you think Chinese Premier Wen Jiabao thinks of His Holiness the Dalai Lama? Everyone looks like an asshole to someone. Don't sweat it.
I think you might be confusing the map and territory here. I would say that the student was seeking enlightenment. In Renzi Zen, this is a very dumb thing to do... you do not go seek enlightenment, you experience it. One cannot be given enlightenment. Thus the teacher appears to teach the student by telling him to do something that ANY SANE PERSON would have replied to with "You go fuck off Zen Master". The student, focused entirely on winning by gaining 'enlightenment' in some quick fashion, runs off, though without thought and with complete trust in his Spiritual Leader... and sits in a old broken down crappy building, then shit falls on his head. He goes through ALL of this, sitting in a stagnant old house, doing nothing, learning nothing... just sitting. The shit falls on his head... and he still sits there, waiting for the magics of enlightenment to show up.
It is only when another person comments on the situation, that he becomes enlightened. "Some say he is a holy man" (nothing enlightening there) "some say he is a shithead" (a word that suddenly describes the student physically and metaphorically). The enlightenment, was not "I CAN DO WHAT I WANT AND SOME PEOPLE WILL THINK I'M AWESOME", but rather "Holy Shit, I've been a dumbass".
It reminds me of the lovely painting that Hagbard had hanging in his lounge, where Moses has the One Commandment given by God: "Think For Yourself, Schmuck!"
Discordians are everywhere. You can find them because they stick out from the crowd by sticking apart fromthe crowd. Sometimes they form Cabals, sometimes their Cabals are one person. They are philosophers, scientists, magicians, artists, maniacs and weirdos. Dynamic, creative people who struggle with understanding why there is so much strife and discord in the world. These people are more likely to recognize the genius of this Erisian madness. These are the people who get Discordia.
Only those people are Discordian?
I notice sometimes that people do seem to get this idea... that the tribe of philosophers, clowns, etc are The Discordians. Yet, this doesn't seem correct to me, in retrospect. Those are the people writing the book, this tribe of madmen interested in the doings of She What Done It All. We could say that they are the Joshua Norton Cabal, or POEE. However, if one chooses to accept what is written on the topic... Every Man, Woman and Child is a Discordian... the only difference lies in their House, The Rising Podge or The Rising Hodge.

Erisians are fundamentally nice people. They don't pray, because praying tends to get whole villages wiped out. That shows concern for the well-being of others. Another example is the reference to the Brunswick Shrine. If the POEE visit it 5 times, the world ends. Recognizing this, they never visit it. Obviously the end of the world is not desirable.
Well, I can see how you might interpret it that way. Though, based on other Discordian writings from Omar and Bob, I'd guess (IMO) that they were making fun of belief systems through hyperbole, rather than saying "Let's save the villages".
Another way we could look at this, is as a warning against stagnation (Kerry was always railing on about 'doing the same thing...). Perhaps visiting the Shrine five times was the invocation of a repetitive pattern... someone who took the trappings of the erisians and repeated them over and over, as though that would bring enlightenment. Perhaps, if they do the same damned Discordian thing Over and Over (with the number 5 indicating Discordian Magics), their world will be destroyed... IE their freedom will be impaired, their choice will be replaced by routine. Their ability to think for themselves, replaced by rote repetition of religions duty.
Or, maybe they were just being silly. Most of the original PD was written as interoffice memos and jokes between co-workers. It might be a bad idea to deconstruct it too far... sometimes a windmill is just a really, really big lawn ornament.
The rest of your assessment is meh, for me... I think that some Discordians like the 'all creative' viewpoint. RAW certianly tended toward a more optimistic view like that. Personally, I find Destruction to be as important as Creation (and I'm still an optimist)... Igne Natura Renovatur Integra.
Also, you're missing, what I consider as two key points on the King Kong riff.....
