For webpage to PDF, that may have been me recommending the PDF Download add-on, which does a decent job converting webpages to docs, if you don't mind that happens through Nitro PDF's server. You can get it straight from Firefox's own Tools -> Add-ons menu. Otherwise:
http://www.pdfdownload.org/
All the other questions have been answered, methinks. As far as audio goes: there's no real speaker and there's no headphone jack and there's no bluetooth for a headset... how would it be audible even if you could generate it...