Hi Salvatore,
Yes this is possible by changing the target mapping.
You should target the nmsAppSubscriptionRcp table directly instead of creating a Join with the recipient table.
So the new mapping would look like :

As opposed to the OOB Mapping of :

For the second point, I think this is possible as I see implementations with extended app subscription fields already present with data being fed into that table.
Regards,
Adhiyan