I want to be able to share the URL with my sales team so they can use it in their own email correspondence, without having to send people to a form or page to download. Is this doable?
You can only track direct asset links sent outside of Mkto if you attach special tracking information, as I explored here: http://blog.teknkl.com/tracking-clicks-non-marketo-emails/ and use a redirector page.
Otherwise, the link can't be tracked to the lead, since it doesn't carry any identifying information. And PDFs don't run Munchkin, thus the requirement of a redirector page (always better all around).
Use Sanford Whiteman's redirector page technique: http://blog.teknkl.com/stop-using-direct-download-links-unless-you-like-losing-tracking/ . This even works in standalone emails (email sent outside of Marketo). Of course, only known/cookied users will be tracked - but I assume you're just referring to existing/known users anyway since there wouldn't be a record to associate this click activity to.