Good morning, David!
If you have program in Marketo setup and connected to the GoToWebinar event, we can definitely get most (if not all) of this done.
To be more specific:
1. Any registrations done on the Marketo landing page that mark the leads as registered will be synced to the GTW event.
2. Any registrations done on the non-Marketo GTW will NOT be pushed to Marketo. We will get information on these leads after the event is complete when GTW sends the attended/no-show report back to Marketo.
3. Those who register on the Marketo page and then get their registration status synced over to GTW will get any alerts/notifications from GTW that you have setup to be send out after a person registers.
Let me know if you have any other questions!
Jesse
Technical Support Engineer - Premier Support Team