Hi Glen,
I advice to go for scenario 2. Using Outbound InfoSource is the right approach for connecting an SPO to a subsequent InfoProvider. This way a correct functioning of the delta mechanism can be expected.
You will also need to create multiple DTPs from every PartProvider to the subsequent InfoProvider.
You may try out scenario 1 and see if it really works for all PartProviders and also using a delta mechanism. From my experience, it does not work correctly. That is why I suggest scenario 2.
Best regards,
Sander