Your examples don't show with JavaScript turned off. (this isn't to be pedantic, this is how I and many others browse)
Sorry to point this out, but doesn't your section "@font-face Use and Abuse" rule out embedding typefaces like Gotham?
Yep, I swapped it out at the last second. The previous typeface allowed embedding without OTF and TTF. Someone raised the issue over Twitter and it is now being tracked on GitHub.
thank you for this excellent submission and write up - you've now given me some great suggestions to tackle this week on my Web app.