Hi Scott,
I'm putting the finishing touches on a developer's blog post for situation 1 right now, and it should be up some time in the next week or so. Regarding 2, are your users already cookied and IDed to user records(with email addresses) in your web app? If so you can use syncLead to send the Email and the Marketo Cookie down to Marketo to quickly associate your records to Marketo's web activity tracking: http://developers.marketo.com/documentation/soap/synclead/