We are currently setting up an EDM with links to articles that are behind a required login. Does anyone know if there's a way to pass the login credentials from Marketo so that the links can be sent direct to each individual article?
This depends on how the EDM software processes logins. Nothing prevents you from syncing usernames and passwords to Marketo and then appending them to query strings on your links. However, this isn't common practice, and in particular if the EDM stores passwords securely (salted + hashed) they never exist in a plain-text form, so they will never be able to be passed to Marketo and into a URL.