Was there any solution to this?
Leads become known in Marketo when they fill out a form or click a link in a Marketo email. If you want to manually connect them, your other option would be to use the Munchkin API using the Associate Lead call: Lead Tracking (Munchkin) » Marketo Developers
Can you or someone who knows how to do a screenshare video or screenshot explainer on how to do the Associate Lead call. I see it referenced a lot, but have not seen anyone really explain how you would do this.