I am not sure I understand what you are trying to do. You will need to add leads to the engagement program before they can run through and receive content. Also, we don't support adding email programs to the engagement program.
I figured this out and actually tweaked the framework of my program so it's all resolved now.
how did you get this to work?
If I'm using a single email program that will apply to multiple engagement tracks --- do I need to have separate smart campaigns - per engagement track - that refine/define who the emails will be sent to? Or can i have a catch-all filter within the smart list of the email program's outbound email processing that consists of "member of engagement program is ..." and then lists ALL ten engagement tracks?