You mention the company had developed free content assets to 'bait the hook' for optins already. So whether it's using the most valuable piece or pieces of already-created content or ruining a contest to give away one or several premium pieces of content or free registrations/downloads to the course; create a squeeze page for option/sign ups with either immediate download of that content or registration into the contest/giveaway.

A couple of optin apps I have experience and success using are option monster and pop up domination.

Both work as plugins for WordPress and pop up domination can also be installed standalone to work on any website/page via embedding a simple longer of generated javascript.

A great way to use either app is an "inline" form on your page along with graphics/copy and an exit intent pop up that prompts a user as they attempt to leave the page.

Good luck!