My non-techie friends are clueless unless I tell them.
You're missing one MAJOR detail. IF Apple was so concerned about the secrecy where these parts leaks are concerned, they'd simply send a take down request and follow it up with a C&D if it was ignored. This proves in my mind that Cook clearly wasn't referring to parts leaks when he made that statement.
This is getting off topic, but I don't see how a C&D letter to a random website in Asia would accomplish much. Assuming they actually follow it, they'd just post the photos and videos to a different site. As for vids on YouTube, that'd be a tacit admission that the parts are real (as pointed out above). By the way, aren't you also making a leap of faith in assuming Cook doesn't care about parts leaks?
As for the headphones, yes you can make a loudspeaker without a vent port. That design can have very accurate sound reproduction, but it's not terribly efficient. The driver isn't pulling on a vacuum, just slightly rarefied air.